System and method for data compression based on data position in frames structure

ABSTRACT

Method and system for lossless and stateless compression scheme is used with a fixed-length data such as frames. Frames having a payload of M bits length are mapped into a payload of N bits length, where N&lt;M. The N bits payload of each received frame is extracted, and mapped using a memory, PLD, or a processor, to reconstruct the uncompressed M bits payload, and to form the original frame. The reconstruction may use a set of N coefficients that are each multiplied by the corresponding received payload bit, and summarized modulo-2 to obtain the original pre-compressed M payload bits. The method and system may be used with a vehicle bus, such as Controller Area Network (CAN). The compressed frames may use the same or different protocol than the uncompressed ones, and may further carry an additional code such as metadata, error detection or correction code, or authentication related code.

RELATED APPLICATIONS

This patent application is a national phase application of a PCTApplication No. PCT/IL2019/051301 that was filed on Nov. 27, 2019 andwhich claims the benefit of U.S. Provisional Application Serial No. U.S.Provisional Application Ser. No. 62/794,651 that was filed on Jan. 20,2019, and of U.S. Provisional Application Ser. No. 62/873,029 filed Jul.11, 2019, which are all hereby incorporated herein by reference in theirentirety.

TECHNICAL FIELD

This disclosure relates generally to an apparatus and method fordata-link layer (OSI Layer 2) based compression and decompression, andin particular, but not exclusive, to compression or decompression basedon data location within a frame, such as in automotive bus protocol.

BACKGROUND

Unless otherwise indicated herein, the materials described in thissection are not prior art to the claims in this application, and are notadmitted to be prior art by inclusion in this section. The data layer,or layer 2, is the second layer of the seven-layer Open SystemsInterconnection (OSI) model of computer networking. This layer is theprotocol layer that transfers data between adjacent network nodes in awide area network (WAN) or between nodes on the same local area network(LAN) segment. The data link layer provides the functional andprocedural means to transfer data between network entities and mightprovide the means to detect and possibly correct errors that may occurin the physical layer. The data link layer is concerned with localdelivery of frames between nodes on the same level of the network.Data-link frames, as these protocol data units are called, do not crossthe boundaries of a local area network. Inter-network routing and globaladdressing are higher-layer functions, allowing data-link protocols tofocus on local delivery, addressing, and media arbitration. Data-linkprotocols may specify how devices detect and recover from collisions,and may provide mechanisms to reduce or prevent them. Examples of datalink protocols are Ethernet for local area networks (multi-node), thePoint-to-Point Protocol (PPP), HDLC and ADCCP for point-to-point(dual-node) connections. In the Internet Protocol Suite (TCP/IP), thedata link layer functionality is contained within the link layer, thelowest layer of the descriptive model.

A frame header typically contains source and destination addresses thatindicate which device originated the frame and which device is expectedto receive and process it. In contrast to the hierarchical and routableaddresses of the network layer, layer-2 addresses are flat, meaning thatno part of the address can be used to identify the logical or physicalgroup to which the address belongs. The data link thus provides datatransfer across the physical link. That transfer can be reliable orunreliable; many data-link protocols do not have acknowledgments ofsuccessful frame reception and acceptance, and some data-link protocolsmight not even have any form of checksum to check for transmissionerrors. In those cases, higher-level protocols must provide flowcontrol, error checking, and acknowledgments and retransmission.

In some networks, such as IEEE 802 local area networks, the data linklayer is described in more detail with media access control (MAC) andlogical link control (LLC) sublayers; this means that the IEEE 802.2 LLCprotocol can be used with all of the IEEE 802 MAC layers, such asEthernet, token ring, IEEE 802.11, etc., as well as with some non-802MAC layers such as FDDI. Other data-link-layer protocols, such as HDLC,are specified to include both sublayers, although some other protocols,such as Cisco HDLC, use HDLC's low-level framing as a MAC layer incombination with a different LLC layer. In the ITU-T G.hn standard,which provides a way to create a high-speed (up to 1 Gigabit/s) localarea network using existing home wiring (power lines, phone lines andcoaxial cables), the data link layer is divided into three sub-layers(application protocol convergence, logical link control and media accesscontrol).

The data link layer has two sublayers: Logical Link Control (LLC) andMedia Access Control (MAC). The uppermost sublayer, LLC, multiplexesprotocols running at the top of data link layer, and optionally providesflow control, acknowledgment, and error notification. The LLC providesaddressing and control of the data link. It specifies which mechanismsare to be used for addressing stations over the transmission medium andfor controlling the data exchanged between the originator and recipientmachines.

MAC may refer to the sublayer that determines who is allowed to accessthe media at any one time (e.g., CSMA/CD). Other times it refers to aframe structure delivered based on MAC addresses inside. There aregenerally two forms of media access control: distributed andcentralized. The Media Access Control sublayer also determines where oneframe of data ends and the next one starts—frame synchronization. Thereare four means of frame synchronization: time based, character counting,byte stuffing and bit stuffing.

The time based approach simply puts a specified amount of time betweenframes. The major drawback of this is that new gaps can be introduced orold gaps can be lost due to external influences. Character countingsimply notes the count of remaining characters in the frame's header.This method, however, is easily disturbed if this field gets faulty insome way, thus making it hard to keep up synchronization. Byte stuffingprecedes the frame with a special byte sequence such as DLE STX andsucceeds it with DLE ETX. Appearances of DLE (byte value 0x10) have tobe escaped with another DLE. The start and stop marks are detected atthe receiver and removed as well as the inserted DLE characters.Similarly, bit stuffing replaces these start and end marks with flagconsisting of a special bit pattern (e.g. a 0, six 1 bits and a 0).Occurrences of this bit pattern in the data to be transmitted areavoided by inserting a bit. To use the example where the flag is01111110, a ‘0’ is inserted after 5 consecutive 1's in the data stream.The flags and the inserted 0's are removed at the receiving end. Thismakes for arbitrary long frames and easy synchronization for therecipient. Note that this stuffed bit is added even if the followingdata bit is ‘0’, which could not be mistaken for a sync sequence, sothat the receiver can unambiguously distinguish stuffed bits from normalbits.

The data link layers further includes mechanisms to detect and evenrecover from transmission errors. For a receiver to detect transmissionerror, the sender must add redundant information (in the form of bits)as an error detection code to the frame sent. When the receiver obtainsa frame with an error detection code it re-computes it and verifieswhether the received error detection code matches the computed errordetection code. If they match the frame is considered to be valid. Anerror detection code can be defined as a function that computes the r(amount of redundant bits) corresponding to each string of N totalnumber of bits. The simplest error detection code is the parity bit,which allows a receiver to detect transmission errors that have affecteda single bit among the transmitted N+r bits. If there are two or morebits in error, the receiver may not be able to detect the transmissionerror.

Frame. A frame is a digital data transmission unit in computernetworking and telecommunication. A frame typically includes framesynchronization features consisting of a sequence of bits or symbolsthat indicate to the receiver the beginning and end of the payload datawithin the stream of symbols or bits it receives. If a receiver isconnected to the system in the middle of a frame transmission, itignores the data until it detects a new frame synchronization sequence.

In the OSI model of computer networking, a frame is the protocol dataunit at the data link layer. Frames are the result of the final layer ofencapsulation before the data is transmitted over the physical layer.Each frame is separated from the next by an interframe gap. A frame is aseries of bits generally composed of framing bits, the packet payload,and a frame check sequence. In telecommunications, specifically inTime-Division Multiplex (TDM) and Time-Division Multiple Access (TDMA)variants, a frame is a cyclically repeated data block that consists of afixed number of time slots, one for each logical TDM channel or TDMAtransmitter. In this context, a frame is typically an entity at thephysical layer. The frame is also an entity for time-division duplex,where the mobile terminal may transmit during some timeslots and receiveduring others. Often, frames of several different sizes are nestedinside each other. For example, when using Point-to-Point Protocol (PPP)over asynchronous serial communication, the eight bits of eachindividual byte are framed by start and stop bits, the payload databytes in a network packet are framed by the header and footer, andseveral packets can be framed with frame boundary octets.

A schematic view of an exemplary frame 10 is shown in FIG. 1. The frame10 is defined as starting with a header 11, including few bits, and endswith a trailer (also known as ‘footer’) 13 bits. The data carried by theframe 10 is referred to as payload 12, and is positioned between theheader 11 and the trailer 13. In the example of the frame 10, thepayload 12 comprises a most LSB bit (or position) a₀ 12 a, which isfollowed by bit or location a₁ 12 b, and then followed by bits (orlocations) a₂ 12 c, a₃ 12 d, and a₄ 12 e. The payload 12 ends with bitsa_(M-3) 12 f, followed by bit or location a_(M-2) 12 g, and ending withthe MSB bit or location a_(M-1) 12 h, totaling of M bits in the payload12. While frame 10 is shown where the LSB bits (or locations) follow theheader 11 and the MSB bits (or locations) precede the trailer 13, framescan equally use a reverse order, where MSB bits (or locations) thatfollow the header 11 and LSB bits (or locations) that precede thetrailer 13. Few locations or bits may be group to form a field having aspecific significance or indication, such as a field ‘A’ 14 a shown toinclude the first LSB bits or locations a₀ 12 a to a₃ 12 d, and a field‘B’ 14 b shown to include the last two MSB bits a_(M-2) 12 g and a_(M-1)12 h. Similarly, single bits may be used as specific indicators, such asbit or location a₄ 12 e shown as an indicator 15.

Packet. A packet is the unit of data passed across the interface betweenthe internet layer and the link layer. It typically includes an IPheader and data, and a packet may be a complete IP datagram or afragment of an IP datagram. A packet is typically a formatted unit ofdata carried by a packet-switched network. When data is formatted intopackets, packet switching is possible and the bandwidth of thecommunication medium can be better shared among users than with circuitswitching.

A packet consists of control information and user data, which is alsoknown as the payload. Control information provides data for deliveringthe payload, for example: source and destination network addresses,error detection codes, and sequencing information. Typically, controlinformation is found in packet headers and trailers. In the seven-layerOSI model of computer networking, packet strictly refers to a data unitat layer 3, the Network Layer. The correct term for a data unit at Layer2, the Data Link Layer, is a frame, and at Layer 4, the Transport Layer,the correct term is a segment or datagram. For the case of TCP/IPcommunication over Ethernet, a TCP segment is carried in one or more IPpackets, which are each carried in one or more Ethernet frames.Different communications protocols use different conventions fordistinguishing between the elements and for formatting the data. Forexample, in Point-to-Point Protocol, the packet is formatted in 8-bitbytes, and special characters are used to delimit the differentelements. Other protocols like Ethernet, establish the start of theheader and data elements by their location relative to the start of thepacket. Some protocols format the information at a bit level instead ofa byte level. A network design can achieve two major results by usingpackets: error detection and multiple host addressing. A packettypically includes various fields such as addresses, Error detection andcorrection, hop counts, priority, length, and payload.

The addresses fields commonly relating to the routing of network packetsrequires two network addresses, the source address of the sending host,and the destination address of the receiving host. Error detection andcorrection is performed at various layers in the protocol stack. Networkpackets may contain a checksum, parity bits or cyclic redundancy checksto detect errors that occur during transmission. At the transmitter, thecalculation is performed before the packet is sent. When received at thedestination, the checksum is recalculated, and compared with the one inthe packet. If discrepancies are found, the packet may be corrected ordiscarded. Any packet loss is dealt with by the network protocol. Underfault conditions packets can end up traversing a closed circuit. Ifnothing was done, eventually the number of packets circulating wouldbuild up until the network was congested to the point of failure. Atime-to-live is a field that is decreased by one each time a packet goesthrough a network node. If the field reaches zero, routing has failed,and the packet is discarded. Ethernet packets have no time-to-live fieldand so are subject to broadcast radiation in the presence of a switchloop. There may be a field to identify the overall packet length.However, in some types of networks, the length is implied by theduration of transmission. Some networks implement quality of service,which can prioritize some types of packets above others. This fieldindicates which packet queue should be used; a high priority queue isemptied more quickly than lower priority queues at points in the networkwhere congestion is occurring. In general, payload is the data that iscarried on behalf of an application. It is usually of variable length,up to a maximum that is set by the network protocol and sometimes theequipment on the route. Some networks can break a larger packet intosmaller packets when necessary.

Physical layer. The Open Systems Interconnection (OSI) model, which isdefined by the International Organization for Standardization (ISO) andis maintained by the identification ISO/IEC 7498-1, includesseven-layers. The physical layer or layer 1 is the first and lowestlayer. The physical layer consists of the basic networking hardware fortransmission technologies of a network. It is a fundamental layerunderlying the logical data structures of the higher level functions ina network. The physical layer defines the electrical and physicalspecifications of the data connection. It defines the relationshipbetween a device and a physical transmission medium (e.g., a copper orfiber optical cable and radio frequency). This includes the layout ofpins, voltages, line impedance, cable specifications, signal timing andsimilar characteristics for connected devices and frequency (5 GHz or2.4 GHz etc.) for wireless devices. It is responsible for transmissionand reception of unstructured raw data in a physical medium. It maydefine transmission mode as simplex, half-duplex, and full duplex. Itfurther defines the network topology as bus, mesh, or ring being some ofthe most common.

The physical layer defines the means of transmitting raw bits ratherthan logical data packets over a physical link connecting network nodes.The bit stream may be grouped into code words or symbols and convertedto a physical signal that is transmitted over a hardware transmissionmedium. The physical layer provides an electrical, mechanical, andprocedural interface to the transmission medium. The major functions andservices performed by the physical layer are bit-by-bit orsymbol-by-symbol delivery, providing a standardized interface tophysical transmission media, including mechanical specification ofelectrical connectors and cables, for example maximum cable length,electrical specification of transmission line signal level andimpedance, radio interface, including electromagnetic spectrum frequencyallocation and specification of signal strength, analog bandwidth,modulation, line coding, bit synchronization in synchronous serialcommunication, start-stop signaling and flow control in asynchronousserial communication, circuit switching, multiplexing, establishment andtermination of circuit switched connections, carrier sense and collisiondetection (utilized by some level 2 multiple access protocols),equalization filtering, training sequences, pulse shaping and othersignal processing of physical signals, forward error correction,bit-interleaving and other channel coding. The physical layer is alsoconcerned with bit rate, point-to-point, multipoint orpoint-to-multipoint line configuration, physical network topology, forexample bus, ring, mesh or star network, serial or parallelcommunication, simplex, half duplex or full duplex transmission mode,and auto-negotiation.

Medium. In a communication network, multiple devices or stations thatimplement some part of the communication protocol are communicating overa transmission medium, which is a transmission path along which a signalpropagates, such as a wire pair, coaxial cable, waveguide, opticalfiber, or radio path. Such a medium may include any material substance,such as fiber-optic cable, twisted-wire pair, coaxial cable,dielectric-slab waveguide, water, and air, which can be used for thepropagation of signals, usually in the form of modulated radio, light,or acoustic waves, from one point to another. A free space is typicallyalso considered as a transmission medium for electromagnetic waves,although it is not a material medium. A medium that consists of aspecialized cable or other structure designed to carry alternatingcurrent of radio frequency, that is, currents with a frequency highenough that their wave nature must be taken into account, is referred toas a transmission line. Transmission lines are commonly used forpurposes such as connecting radio transmitters and receivers with theirantennas.

The transfer of information such as the digital data between two nodesin a network commonly makes use of a line driver for transmitting thesignal to the conductors serving as the transmission medium connectingthe two nodes, and a line receiver for receiving the transmitted signalfrom the transmission medium. The communication may use a proprietaryinterface or preferably an industry standard, which typically definesthe electrical signal characteristics such as voltage level, signalingrate, timing and slew rate of signals, voltage withstanding levels,short-circuit behavior, and maximum load capacitance. Further, theindustry standard may define the interface mechanical characteristicssuch as the pluggable connectors and pin identification and pin-out. Inone example, the module circuit can use an industry or other standardused for interfacing serial binary data signals. Preferably, the linedrivers, the line receivers, and their associated circuitry will beprotected against Electro-Static Discharge (ESD), electromagneticinterference (EMI/EMC) and against faults (fault-protected), and employsproper termination, failsafe scheme and supports live insertion.Preferably, a point-to-point connection scheme is used, wherein a singleline driver is communicating with a single line receiver. However,multi-drop or multi-point configurations may as well be used. Further,the line driver and the line receiver may be integrated into a single IC(Integrated Circuit), commonly known as transceiver IC. A device thattransmits data to a medium typically uses a line driver, which commonlyincludes an electronic amplifier as part of a circuit designed for aload such as a transmission line, and preferably optimized to the mediumused. The output impedance of the amplifier typically matches thecharacteristic impedance of the transmission line. The line drivertypically converts the logic levels used by the module internal digitallogic circuits (e.g., CMOS, TTL, LSTTL and HCMOS) to a signal to betransmitted over the medium. At the receiving device, a line receiver isused which typically converts the received signal to the logic levelsused by the module internal digital logic circuits (e.g., CMOS, TTL,LSTTL and HCMOS). A set of a line driver and a line receiver is commonlyreferred to as, or is part of, a transceiver (transmitter+receiver), andis used in nodes that both transmits digital data to the medium andreceives digital data from the medium. In the case where the signal overthe medium is modulated, a modem (a MOdulator-DEModulator) device isused, which encodes digital information onto an analog carrier signal byvarying their amplitude, frequency, or phase of that carrier. Thedemodulator extracts digital information from a similarly modifiedcarrier. A modem transforms digital signals into a form suitable fortransmission over an analog medium.

Wire. An electrical wire is a single, usually cylindrical, flexiblestrand or rod of metal, typically for carrying electricity andtelecommunications signals. Wire is commonly formed by drawing the metalthrough a hole in a die or draw plate, and wire gauges come in variousstandard sizes, as expressed in terms of a gauge number. Wire comes insolid core, stranded, or braided forms. Although usually circular incross-section, wire can be made in square, hexagonal, flattenedrectangular, or other cross-sections, either for decorative purposes, orfor technical purposes such as high-efficiency voice coils inloudspeakers. A wire pair consists of two like conductors employed toform or serve an electric circuit.

Cable. An electrical cable is an assembly of one or more insulatedconductors, or optical fibers, or a combination of both, within anenveloping jacket, where the conductors or fibers may be used singly orin groups. A typical electrical cable is made of two or more wiresrunning side by side and bonded, twisted, or braided together to form asingle assembly, the ends of which can be connected to two devices,enabling the transfer of electrical signals from one device to theother.

Wireline. Wireline or wired network uses conductors, typically metallicwire conductors, as the transmission medium. The transmission mediumsused in common wirelines include twisted-pair, coaxial cable, stripline,and microstrip. Microstrip is a type of electrical transmission line,which can be fabricated using printed circuit board technology, and isused to convey microwave-frequency signals. It consists of a conductingstrip separated from a ground plane by a dielectric layer known as thesubstrate. Microwave components such as antennas, couplers, filters,power dividers etc. can be formed from microstrip, with the entiredevice existing as the pattern of metallization on the substrate. Astripline circuit uses a flat strip of metal, which is sandwichedbetween two parallel ground planes, where the insulating material of thesubstrate forms a dielectric. The width of the strip, the thickness ofthe substrate and the relative permittivity of the substrate determinethe characteristic impedance of the strip, which is a transmission line.Various cables are described in “Technical Handbook & Catalog” TwelfthEdition published 2006 by Standard Wire & Cable Co., which isincorporated in its entirety for all purposes as if fully set forthherein.

Topology. A wired network is defined by the specific physicalarrangement of the elements (nodes) connected to a network, although thenetworks may differ in physical interconnections, distances betweennodes, transmission rates, and/or signal types. Network topology is thearrangement of the various elements (links, nodes, etc.) of a computernetwork. Essentially, it is the topological structure of a network andmay be depicted physically or logically. Physical topology is theplacement of the various components of a network, including devicelocation and cable installation, while logical topology illustrates howdata flows within a network, regardless of its physical design.Distances between nodes, physical interconnections, transmission rates,or signal types may differ between two networks, yet their topologiesmay be identical. Traditionally, eight basic topologies are identified:point-to-point, bus, star, ring or circular, mesh, tree, hybrid, anddaisy chain.

A point-to-point topology is a configuration where there are only nodesconnected over a dedicated medium. In a bus topology (also known aslinear topology), all nodes, i.e., stations, are connected together by asingle medium. A fully connected topology (also known as fully connectedmesh network), there is a direct path between any two nodes, so thatwith n nodes, there are n(n−1)/2 direct paths. In a ring topology, everynode has exactly two branches connected to it. A ring topology isactually a bus topology in a closed loop, where data travels around thering in one direction. When one node sends data to another, the datapasses through each intermediate node on the ring until it reaches itsdestination. The intermediate nodes repeat (retransmit) the data to keepthe signal strong. Every node is a peer; there is no hierarchicalrelationship of clients and servers. If one node is unable to retransmitdata, it severs communication between the nodes before and after it inthe bus.

A combination of any two or more network topologies is known as hybridtopology. A network topology in which peripheral nodes are connected toa central node, which rebroadcasts all transmissions received from anyperipheral node to all peripheral nodes on the network, including theoriginating node, is referred to as star topology. All peripheral nodesmay thus communicate with all others by transmitting to, and receivingfrom, the central node only. If the star central node is passive, theoriginating node must be able to tolerate the reception of an echo ofits own transmission, delayed by the two-way transmission time, i.e., toand from the central node, plus any delay generated in the central node.An active star network has an active central node that usually has themeans to prevent echo-related problems.

In local area networks where bus topology is used, each node isconnected to a single cable, by the help of interface connectors. Thiscentral cable is the backbone of the network and is known as the bus. Asignal from the source travels in both directions to all nodes connectedon the bus cable until it finds the intended recipient. If the nodeaddress does not match the intended address for the data, the machineignores the data. Alternatively, if the data matches the node address,the data is accepted. Because the bus topology consists of only one ortwo wire, it is rather inexpensive to implement when compared to othertopologies. In a linear bus, all of the nodes of the network areconnected to a common transmission medium which has exactly twoendpoints (this is the ‘bus’, which is also commonly referred to as thebackbone, or trunk)—all data that is transmitted between nodes in thenetwork is transmitted over this common transmission medium and is ableto be received by all nodes in the network simultaneously. In a startopology network, each network node is connected to a central hub with apoint-to-point connection, so effectively every node is indirectlyconnected to every other node with the help of the hub. In startopology, every node is connected to a central node called hub, routeror switch. The switch is the server and the peripherals are the clients.The network does not necessarily have to resemble a star to beclassified as a star network, but all of the nodes on the network mustbe connected to one central device. All traffic that traverses thenetwork passes through the central hub. The hub acts as a signalrepeater. The star topology is considered the easiest topology to designand implement. An advantage of the star topology is the simplicity ofadding additional nodes. The primary disadvantage of the star topologyis that the hub represents a single point of failure.

An example of a multi-point ‘bus’ topology communication over a balancedline, such as according to RS-485, is shown in an arrangement 40 in FIG.4. The wired communication medium 16 comprises two conductors or wires14 a and 14 b, cooperatively connected in a point-to-point topology, andmay form a balanced line such as a UTP or STP. Bus devices ‘A’ 41 a, ‘B’41 b, and ‘C’ 41 c are connected at different points along the medium(or at the medium ends), and are respectively connected to the medium 16by connectors 13 a, 13 b, and 13 c. The bus devices ‘A’ 41 a, ‘B’ 41 b,and ‘C’ 41 c respectively comprises balanced line drivers 41 a, 41 b,and 41 c, and balanced line receivers 42 a, 42 b, and 42 c, that may bepart of respective transceivers 43 a, 43 b, and 43 c, that arerespectively connected to the connectors 13 a, 13 b, and 13 c forcoupling to the medium 16. Impedances such as resistors 19 a and 19 bare connected at both ends of the medium 16 as terminations for matchingto the medium impedance for reducing signal reflections.

Vehicle. A vehicle is a mobile machine that transports people or cargo.Most often, vehicles are manufactured, such as wagons, bicycles, motorvehicles (motorcycles, cars, trucks, buses), railed vehicles (trains,trams), watercraft (ships, boats), aircraft and spacecraft. The vehiclemay be designed for use on land, in fluids, or be airborne, such asbicycle, car, automobile, motorcycle, train, ship, boat, submarine,airplane, scooter, bus, subway, train, or spacecraft. A vehicle mayconsist of, or may comprise, a bicycle, a car, a motorcycle, a train, aship, an aircraft, a boat, a spacecraft, a boat, a submarine, adirigible, an electric scooter, a subway, a train, a trolleybus, a tram,a sailboat, a yacht, or an airplane. Further, a vehicle may be abicycle, a car, a motorcycle, a train, a ship, an aircraft, a boat, aspacecraft, a boat, a submarine, a dirigible, an electric scooter, asubway, a train, a trolleybus, a tram, a sailboat, a yacht, or anairplane.

A vehicle may be a land vehicle typically moving on the ground, usingwheels, tracks, rails, or skies. The vehicle may be locomotion-basedwhere the vehicle is towed by another vehicle or an animal. Propellers(as well as screws, fans, nozzles, or rotors) are used to move on orthrough a fluid or air, such as in watercrafts and aircrafts. The systemdescribed herein may be used to control, monitor or otherwise be partof, or communicate with, the vehicle motion system. Similarly, thesystem described herein may be used to control, monitor or otherwise bepart of, or communicate with, the vehicle steering system. Commonly,wheeled vehicles steer by angling their front or rear (or both) wheels,while ships, boats, submarines, dirigibles, airplanes and other vehiclesmoving in or on fluid or air usually have a rudder for steering. Thevehicle may be an automobile, defined as a wheeled passenger vehiclethat carries its own motor, and primarily designed to run on roads, andhave seating for one to six people. Typically, automobiles have fourwheels, and are constructed to principally transport of people.

Human power may be used as a source of energy for the vehicle, such asin non-motorized bicycles. Further, energy may be extracted from thesurrounding environment, such as solar powered car or aircraft, a streetcar, as well as by sailboats and land yachts using the wind energy.Alternatively or in addition, the vehicle may include energy storage,and the energy is converted to generate the vehicle motion. A commontype of energy source is a fuel, and external or internal combustionengines are used to burn the fuel (such as gasoline, diesel, or ethanol)and create a pressure that is converted to a motion. Another commonmedium for storing energy are batteries or fuel cells, which storechemical energy used to power an electric motor, such as in motorvehicles, electric bicycles, electric scooters, small boats, subways,trains, trolleybuses, and trams.

Aircraft. An aircraft is a machine that is able to fly by gainingsupport from the air. It counters the force of gravity by using eitherstatic lift or by using the dynamic lift of an airfoil, or in a fewcases, the downward thrust from jet engines. The human activity thatsurrounds aircraft is called aviation. Crewed aircraft are flown by anonboard pilot, but unmanned aerial vehicles may be remotely controlledor self-controlled by onboard computers. Aircraft may be classified bydifferent criteria, such as lift type, aircraft propulsion, usage andothers.

Aerostats are lighter than air aircrafts that use buoyancy to float inthe air in much the same way that ships float on the water. They arecharacterized by one or more large gasbags or canopies filled with arelatively low-density gas such as helium, hydrogen, or hot air, whichis less dense than the surrounding air. When the weight of this is addedto the weight of the aircraft structure, it adds up to the same weightas the air that the craft displaces. Heavier-than-air aircraft, such asairplanes, must find some way to push air or gas downwards, so that areaction occurs (by Newton's laws of motion) to push the aircraftupwards. This dynamic movement through the air is the origin of the termaerodyne. There are two ways to produce dynamic upthrust: aerodynamiclift and powered lift in the form of engine thrust.

Aerodynamic lift involving wings is the most common, with fixed-wingaircraft being kept in the air by the forward movement of wings, androtorcraft by spinning wing-shaped rotors sometimes called rotary wings.A wing is a flat, horizontal surface, usually shaped in cross-section asan aerofoil. To fly, air must flow over the wing and generate lift. Aflexible wing is a wing made of fabric or thin sheet material, oftenstretched over a rigid frame. A kite is tethered to the ground andrelies on the speed of the wind over its wings, which may be flexible orrigid, fixed, or rotary.

Gliders are heavier-than-air aircraft that do not employ propulsion onceairborne. Take-off may be by launching forward and downward from a highlocation, or by pulling into the air on a tow-line, either by aground-based winch or vehicle, or by a powered “tug” aircraft. For aglider to maintain its forward air speed and lift, it must descend inrelation to the air (but not necessarily in relation to the ground).Many gliders can ‘soar’—gain height from updrafts such as thermalcurrents. Common examples of gliders are sailplanes, hang gliders andparagliders. Powered aircraft have one or more onboard sources ofmechanical power, typically aircraft engines although rubber andmanpower have also been used. Most aircraft engines are eitherlightweight piston engines or gas turbines. Engine fuel is stored intanks, usually in the wings but larger aircraft also have additionalfuel tanks in the fuselage.

A propeller aircraft use one or more propellers (airscrews) to createthrust in a forward direction. The propeller is usually mounted in frontof the power source in tractor configuration but can be mounted behindin pusher configuration. Variations of propeller layout includecontra-rotating propellers and ducted fans. A Jet aircraft useairbreathing jet engines, which take in air, burn fuel with it in acombustion chamber, and accelerate the exhaust rearwards to providethrust. Turbojet and turbofan engines use a spinning turbine to driveone or more fans, which provide additional thrust. An afterburner may beused to inject extra fuel into the hot exhaust, especially on military“fast jets”. Use of a turbine is not absolutely necessary: other designsinclude the pulse jet and ramjet. These mechanically simple designscannot work when stationary, so the aircraft must be launched to flyingspeed by some other method. Some rotorcrafts, such as helicopters, havea powered rotary wing or rotor, where the rotor disc can be angledslightly forward so that a proportion of its lift is directed forwards.The rotor may, similar to a propeller, be powered by a variety ofmethods such as a piston engine or turbine. Experiments have also usedjet nozzles at the rotor blade tips.

A vehicle may include a hood (a.k.a. bonnet), which is the hinged coverover the engine of motor vehicles that allows access to the enginecompartment (or trunk on rear-engine and some mid-engine vehicles) formaintenance and repair. A vehicle may include a bumper, which is astructure attached, or integrated to, the front and rear of anautomobile to absorb impact in a minor collision, ideally minimizingrepair costs. Bumpers also have two safety functions: minimizing heightmismatches between vehicles and protecting pedestrians from injury. Avehicle may include a cowling, which is the covering of a vehicle'sengine, most often found on automobiles and aircraft. A vehicle mayinclude a dashboard (also called dash, instrument panel, or fascia),which is a control panel placed in front of the driver of an automobile,housing instrumentation and controls for operation of the vehicle. Avehicle may include a fender that frames a wheel well (the fenderunderside). Its primary purpose is to prevent sand, mud, rocks, liquids,and other road spray from being thrown into the air by the rotatingtire. Fenders are typically rigid and can be damaged by contact with theroad surface. Instead, flexible mud flaps are used close to the groundwhere contact may be possible. A vehicle may include a quarter panel(a.k.a. rear wing), which is the body panel (exterior surface) of anautomobile between a rear door (or only door on each side for two-doormodels) and the trunk (boot) and typically wraps around the wheel well.Quarter panels are typically made of sheet metal, but are sometimes madeof fiberglass, carbon fiber, or fiber-reinforced plastic. A vehicle mayinclude a rocker, which is the body section below the base of the dooropenings. A vehicle may include a spoiler, which is an automotiveaerodynamic device whose intended design function is to ‘spoil’unfavorable air movement across a body of a vehicle in motion, usuallydescribed as turbulence or drag. Spoilers on the front of a vehicle areoften called air dams. Spoilers are often fitted to race andhigh-performance sports cars, although they have become common onpassenger vehicles as well. Some spoilers are added to cars primarilyfor styling purposes and have either little aerodynamic benefit or evenmake the aerodynamics worse. The trunk (a.k.a. boot) of a car is thevehicle's main storage compartment. A vehicle door is a type of door,typically hinged, but sometimes attached by other mechanisms such astracks, in front of an opening, which is used for entering and exiting avehicle. A vehicle door can be opened to provide access to the opening,or closed to secure it. These doors can be opened manually, or poweredelectronically. Powered doors are usually found on minivans, high-endcars, or modified cars. Car glass includes windscreens, side and rearwindows, and glass panel roofs on a vehicle. Side windows can be eitherfixed or be raised and lowered by depressing a button (power window) orswitch or using a hand-turned crank.

Autonomous car. An autonomous car (also known as a driverless car,self-driving car, or robotic car) is a vehicle that is capable ofsensing its environment and navigating without human input. Autonomouscars use a variety of techniques to detect their surroundings, such asradar, laser light, GPS, odometry, and computer vision. Advanced controlsystems interpret sensory information to identify appropriate navigationpaths, as well as obstacles and relevant signage. Autonomous cars havecontrol systems that are capable of analyzing sensory data todistinguish between different cars on the road, which is very useful inplanning a path to the desired destination. Among the potential benefitsof autonomous cars is a significant reduction in traffic collisions; theresulting injuries; and related costs, including a lower need forinsurance. Autonomous cars are also predicted to offer major increasesin traffic flow; enhanced mobility for children, the elderly, disabledand poor people; the relief of travelers from driving and navigationchores; lower fuel consumption; significantly reduced needs for parkingspace in cities; a reduction in crime; and the facilitation of differentbusiness models for mobility as a service, especially those involved inthe sharing economy.

Modern self-driving cars generally use Bayesian SimultaneousLocalization And Mapping (SLAM) algorithms, which fuse data frommultiple sensors and an off-line map into current location estimates andmap updates. SLAM with Detection and Tracking of other Moving Objects(DATMO), which also handles things such as cars and pedestrians, is avariant being developed by research at Google. Simpler systems may useroadside Real-Time Locating System (RTLS) beacon systems to aidlocalization. Typical sensors include LIDAR and stereo vision, GPS andIMU. Visual object recognition uses machine vision including neuralnetworks.

The term ‘Dynamic driving task’ includes the operational (steering,braking, accelerating, monitoring the vehicle and roadway) and tactical(responding to events, determining when to change lanes, turn, usesignals, etc.) aspects of the driving task, but not the strategic(determining destinations and waypoints) aspect of the driving task. Theterm ‘Driving mode’ refers to a type of driving scenario withcharacteristic dynamic driving task requirements (e.g., expresswaymerging, high speed, cruising, low speed traffic jam, closed-campusoperations, etc.). The term ‘Request to intervene’ refers tonotification by the automated driving system to a human driver that s/heshould promptly begin or resume performance of the dynamic driving task.

The SAE International standard J3016, entitled: “Taxonomy andDefinitions for Terms Related to On-Road Motor Vehicle Automated DrivingSystems” [Revised 2016 September], which is incorporated in its entiretyfor all purposes as if fully set forth herein, describes six differentlevels (ranging from none to fully automated systems), based on theamount of driver intervention and attentiveness required, rather thanthe vehicle capabilities. The levels are further described in a table 30in FIG. 3. Level 0 refers to automated system issues warnings but has novehicle control, while Level 1 (also referred to as “hands on”) refersto driver and automated system that shares control over the vehicle. Anexample would be Adaptive Cruise Control (ACC) where the driver controlssteering and the automated system controls speed. Using ParkingAssistance, steering is automated while speed is manual. The driver mustbe ready to retake full control at any time. Lane Keeping Assistance(LKA) Type II is a further example of level 1 self-driving.

In Level 2 (also referred to as “hands off”), the automated system takesfull control of the vehicle (accelerating, braking, and steering). Thedriver must monitor the driving and be prepared to immediately interveneat any time if the automated system fails to respond properly. In Level3 (also referred to as “eyes off”), the driver can safely turn theirattention away from the driving tasks, e.g. the driver can text or watcha movie. The vehicle will handle situations that call for an immediateresponse, like emergency braking. The driver must still be prepared tointervene within some limited time, specified by the manufacturer, whencalled upon by the vehicle to do so. A key distinction is between level2, where the human driver performs part of the dynamic driving task, andlevel 3, where the automated driving system performs the entire dynamicdriving task. Level 4 (also referred to as “mind off”) is similar tolevel 3, but no driver attention is ever required for safety, i.e., thedriver may safely go to sleep or leave the driver's seat. Self-drivingis supported only in limited areas (geofenced) or under specialcircumstances, such as traffic jams. Outside of these areas orcircumstances, the vehicle must be able to safely abort the trip, i.e.,park the car, if the driver does not retake control. In Level 5 (alsoreferred to as “wheel optional”), no human intervention is required. Anexample would be a robotic taxi.

An autonomous vehicle and systems having an interface for payloads thatallows integration of various payloads with relative ease are disclosedin U.S. Patent Application Publication No. 2007/0198144 to Norris et al.entitled: “Networked multi-role robotic vehicle”, which is incorporatedin its entirety for all purposes as if fully set forth herein. There isa vehicle control system for controlling an autonomous vehicle,receiving data, and transmitting a control signal on at least onenetwork. A payload is adapted to detachably connect to the autonomousvehicle, the payload comprising a network interface configured toreceive the control signal from the vehicle control system over the atleast one network. The vehicle control system may encapsulate payloaddata and transmit the payload data over the at least one network,including Ethernet or CAN networks. The payload may be a laser scanner,a radio, a chemical detection system, or a Global Positioning Systemunit. In certain embodiments, the payload is a camera mast unit, wherethe camera communicates with the autonomous vehicle control system todetect and avoid obstacles. The camera mast unit may be interchangeable,and may include structures for receiving additional payload components.

Automotive electronics. Automotive electronics involves anyelectrically-generated systems used in vehicles, such as groundvehicles. Automotive electronics commonly involves multiple modular ECUs(Electronic Control Unit) connected over a network such as EngineControl Modules (ECM) or Transmission Control Modules (TCM). Automotiveelectronics or automotive embedded systems are distributed systems, andaccording to different domains in the automotive field, they can beclassified into Engine electronics, Transmission electronics, Chassiselectronics, Active safety, Driver assistance, Passenger comfort, andEntertainment (or infotainment) systems.

One of the most demanding electronic parts of an automobile is theEngine Control Unit. Engine controls demand one of the highest real timedeadlines, as the engine itself is a very fast and complex part of theautomobile. The computing power of the engine control unit is commonlythe highest, typically a 32-bit processor, that typically controls inreal-time in a diesel engine the Fuel injection rate, Emission control,NOx control, Regeneration of oxidation catalytic converter, Turbochargercontrol, Throttle control, and Cooling system control. In a gasolineengine, the engine control typically involves Lambda control, OBD(On-Board Diagnostics), Cooling system control, Ignition system control,Lubrication system control, Fuel injection rate control, and Throttlecontrol.

An engine ECU typically connects to, or includes, sensors that activelymonitor in real-time engine parameters such as pressure, temperature,flow, engine speed, oxygen level and NOx level, plus other parameters atdifferent points within the engine. All these sensor signals areanalyzed by the ECU, which has the logic circuits to do the actualcontrolling. The ECU output is commonly connected to different actuatorsfor the throttle valve, EGR valve, rack (in VGTs), fuel injector (usinga pulse-width modulated signal), dosing injector, and more.

Transmission electronics involves control of the transmission system,mainly the shifting of the gears for better shift comfort and to lowertorque interrupt while shifting. Automatic transmissions use controlsfor their operation, and many semi-automatic transmissions having afully automatic clutch or a semi-auto clutch (declutching only). Theengine control unit and the transmission control typically exchangemessages, sensor signals and control signals for their operation.Chassis electronics typically includes many sub-systems that monitorvarious parameters and are actively controlled, such as ABS—Anti-lockBraking System, TCS—Traction Control System, EBD—Electronic BrakeDistribution, and ESP—Electronic Stability Program. Active safetysystems involve modules that are ready-to-act when there is a collisionin progress, or used to prevent it when it senses a dangerous situation,such as Air bags, Hill descent control, and Emergency brake assistsystem. Passenger comfort systems involve, for example, Automaticclimate control, Electronic seat adjustment with memory, Automaticwipers, Automatic headlamps—adjusts beam automatically, and Automaticcooling—temperature adjustment. Infotainment systems include systemssuch as Navigation system, Vehicle audio, and Information access.

Automotive electric and electronic technologies and systems aredescribed in a book published by Robert Bosch GmbH (5^(th) Edition, July2007) entitled: “Bosch Automotive Electric and Automotive Electronics”[ISBN—978-3-658-01783-5], which is incorporated in its entirety for allpurposes as if fully set forth herein.

ECU. In automotive electronics, an Electronic Control Unit (ECU) is ageneric term for any embedded system that controls one or more of theelectrical system or subsystems in a vehicle such as a motor vehicle.Types of ECU include Electronic/engine Control Module (ECM) (sometimesreferred to as Engine Control Unit—ECU, which is distinct from thegeneric ECU—Electronic Control Unit), Airbag Control Unit (ACU),Powertrain Control Module (PCM), Transmission Control Module (TCM),Central Control Module (CCM), Central Timing Module (CTM), ConvenienceControl Unit (CCU), General Electronic Module (GEM), Body Control Module(BCM), Suspension Control Module (SCM), Door Control Unit (DCU),Powertrain Control Module (PCM), Electric Power Steering Control Unit(PSCU), Seat Control Unit, Speed Control Unit (SCU), Suspension ControlModule (SCM), Telematic Control Unit (TCU), Telephone Control Unit(TCU), Transmission Control Unit (TCU), Brake Control Module (BCM orEBCM; such as ABS or ESC), Battery management system, control unit, orcontrol module.

A microprocessor or a microcontroller serves as a core of an ECU, anduses a memory such as SRAM, EEPROM, and Flash. An ECU is power fed by asupply voltage, and includes or connects to sensors using analog anddigital inputs. In addition to a communication interface, an ECUtypically includes a relay, H-Bridge, injector, or logic drivers, oroutputs for connecting to various actuators.

ECU technology and applications is described in the M. Tech. Projectfirst stage report (EE696) by Vineet P. Aras of the Department ofElectrical Engineering, Indian Institute of Technology Bombay, datedJuly 2004, entitled: “Design of Electronic Control Unit (ECU) forAutomobiles—Electronic Engine Management system”, and in NationalInstruments paper published Nov. 7, 2009 entitled: “ECU Designing andTesting using National Instruments Products”, which are bothincorporated in their entirety for all purposes as if fully set forthherein. ECU examples are described in a brochure by Sensor-TechnikWiedemann Gmbh (headquartered in Kaufbeuren, Germany) dated 20110304 GBentitled “Control System Electronics”, which is incorporated in itsentirety for all purposes as if fully set forth herein. An ECU or aninterface to a vehicle bus may use a processor such as the MPC5748Gcontroller available from Freescale Semiconductor, Inc. (headquarteredin Tokyo, Japan, and described in a data sheet Document Number MPC5748GRev. 2, 05/2014 entitled: “MPC5748 Microcontroller Datasheet”, which isincorporated in its entirety for all purposes as if fully set forthherein.

OSEK/VDX. OSEK/VDX, formerly known as OSEK (Offene Systeme and derenSchnittstellen für die Elektronik in Krafifahrzeugen; in English: “OpenSystems and their Interfaces for the Electronics in Motor Vehicles”)OSEK is an open standard, published by a consortium founded by theautomobile industry for an embedded operating system, a communicationsstack, and a network management protocol for automotive embeddedsystems. OSEK was designed to provide a standard software architecturefor the various electronic control units (ECUs) throughout a car.

The OSEK standard specifies interfaces to multitasking functions—genericI/O and peripheral access—and thus remains architecture dependent. OSEKsystems are expected to run on chips without memory protection. Featuresof an OSEK implementation can be usually configured at compile-time. Thenumber of application tasks, stacks, mutexes, etc., is staticallyconfigured; it is not possible to create more at run time. OSEKrecognizes two types of tasks/threads/compliance levels: basic tasks andenhanced tasks. Basic tasks never block; they “run to completion”(coroutine). Enhanced tasks can sleep and block on event objects. Theevents can be triggered by other tasks (basic and enhanced) or interruptroutines. Only static priorities are allowed for tasks, andFirst-In-First-Out (FIFO) scheduling is used for tasks with equalpriority. Deadlocks and priority inversion are prevented by priorityceiling (i.e. no priority inheritance). The specification usesISO/ANSI-C-like syntax; however, the implementation language of thesystem services is not specified. OSEK/VDX Network Managementfunctionality is described in a document by OSEK/VDX NM Concept & API2.5.2 (Version 2.5.3, 26th July 2004) entitled: “Open Systems and theCorresponding Interfaces for Automotive Electronics—NetworkManagement—Concept and Application Programming Interface”, which isincorporated in its entirety for all purposes as if fully set forthherein. Some parts of the OSEK are standardized as part of ISO 17356standard series entitled: “Road vehicles—Open interface for embeddedautomotive applications”, such as ISO 17356-1 standard (First edition,2005 Jan. 15) entitled: “Part 1: General structure and terms,definitions and abbreviated terms”, ISO 17356-2 standard (First edition,2005 May 1) entitled: “Part 2: OSEK/VDX specifications for binding OS,COM and NM”, ISO 17356-3 standard (First edition, 2005 Nov. 1) entitled:“Part 3: OSEK/VDX Operating System (OS)”, and ISO 17356-4 standard(First edition, 2005 Nov. 1) entitled: “Part 4: OSEK/VDX Communication(COM)”, which are all incorporated in their entirety for all purposes asif fully set forth herein.

AUTOSAR. AUTOSAR (Automotive Open System Architecture) is a worldwidedevelopment partnership of automotive interested parties founded in2003. It pursues the objective of creating and establishing an open andstandardized software architecture for automotive electronic controlunits excluding infotainment. Goals include the scalability to differentvehicle and platform variants, transferability of software, theconsideration of availability and safety requirements, a collaborationbetween various partners, sustainable utilization of natural resources,maintainability throughout the whole “Product Life Cycle”.

AUTOSAR provides a set of specifications that describe basic softwaremodules, defines application interfaces, and builds a common developmentmethodology based on standardized exchange format. Basic softwaremodules made available by the AUTOSAR layered software architecture canbe used in vehicles of different manufacturers and electronic componentsof different suppliers, thereby reducing expenditures for research anddevelopment, and mastering the growing complexity of automotiveelectronic and software architectures. Based on this guiding principle,AUTOSAR has been devised to pave the way for innovative electronicsystems that further improve performance, safety and environmentalfriendliness and to facilitate the exchange and update of software andhardware over the service life of the vehicle. It aims to be preparedfor the upcoming technologies and to improve cost-efficiency withoutmaking any compromise with respect to quality.

AUTOSAR uses a three-layered architecture: Basic Software—standardizedsoftware modules (mostly) without any functional job itself that offersservices necessary to run the functional part of the upper softwarelayer; Runtime environment—Middleware which abstracts from the networktopology for the inter- and intra-ECU information exchange between theapplication software components and between the Basic Software and theapplications; and Application Layer—application software components thatinteract with the runtime environment. System Configuration Descriptionincludes all system information and the information that must be agreedbetween different ECUs (e.g. definition of bus signals). ECU extract isthe information from the System Configuration Description needed for aspecific ECU (e.g. those signals where a specific ECU has access to).ECU Configuration Description contains all basic software configurationinformation that is local to a specific ECU. The executable software canbe built from this information, the code of the basic software modulesand the code of the software components. The AUTOSAR specifications aredescribed in Release 4.2.2 released 31 Jan. 2015 by the AUTOSARconsortium entitled: “Release 4.2 Overview and Revision History”, whichis incorporated in its entirety for all purposes as if fully set forthherein.

Vehicle bus. A vehicle bus is a specialized internal (in-vehicle)communications network that interconnects components inside a vehicle(e.g., automobile, bus, train, industrial or agricultural vehicle, ship,or aircraft). Special requirements for vehicle control such as assuranceof message delivery, of non-conflicting messages, of minimum time ofdelivery, of low cost, and of EMF noise resilience, as well as redundantrouting and other characteristics mandate the use of less commonnetworking protocols. A vehicle bus typically connects the various ECUsin the vehicle. Common protocols include Controller Area Network (CAN),Local Interconnect Network (LIN) and others. Conventional computernetworking technologies (such as Ethernet and TCP/IP) may as well beused.

Any in-vehicle internal network that interconnects the various devicesand components inside the vehicle may use any of the technologies andprotocols described herein. Common protocols used by vehicle busesinclude a Control Area Network (CAN), FlexRay, and a Local InterconnectNetwork (LIN). Other protocols used for in-vehicle are optimized formultimedia networking such as MOST (Media Oriented Systems Transport).The CAN is described in the Texas Instrument Application Report No.SLOA101A entitled: “Introduction to the Controller Area Network (CAN)”,and may be based on, may be compatible with, or may be according to, ISO11898 standards, ISO 11992-1 standard, SAE J1939 or SAE J2411 standards,which are all incorporated in their entirety for all purposes as iffully set forth herein. The LIN communication may be based on, may becompatible with, or according to, ISO 9141, and is described in “LINSpecification Package—Revision 2.2A” by the LIN Consortium, which areall incorporated in their entirety for all purposes as if fully setforth herein. In one example, the DC power lines in the vehicle may alsobe used as the communication medium, as described for example in U.S.Pat. No. 7,010,050 to Maryanka, entitled: “Signaling over NoisyChannels”, which is incorporated in its entirety for all purposes as iffully set forth herein.

CAN. A controller area network (CAN bus) is a vehicle bus standarddesigned to allow microcontrollers and devices to communicate with eachother in applications without a host computer. It is a message-basedprotocol, designed originally for multiplex electrical wiring withinautomobiles, but is also used in many other contexts. CAN bus is one offive protocols used in the on-board diagnostics (OBD)-II vehiclediagnostics standard. CAN is a multi-master serial bus standard forconnecting Electronic Control Units [ECUs] also known as nodes. Two ormore nodes are required on the CAN network to communicate. Thecomplexity of the node can range from a simple I/O device up to anembedded computer with a CAN interface and sophisticated software. Thenode may also be a gateway allowing a standard computer to communicateover a USB or Ethernet port to the devices on a CAN network. All nodesare connected to each other through a two-wire bus. The wires are 120Ωnominal twisted pair. Implementing CAN is described in an ApplicationNote (AN10035-0-2/12(0) Rev. 0) published 2012 by Analog Devices, Inc.entitled: “Controller Area Network (CAN) Implementation Guide—by Dr.Conal Watterson”, which is incorporated in its entirety for all purposesas if fully set forth herein.

CAN transceiver is defined by ISO 11898-2/3 Medium Access Unit [MAU]standards, and in receiving, converts the levels of the data streamreceived from the CAN bus to levels that the CAN controller uses. Itusually has protective circuitry to protect the CAN controller, and intransmitting state converts the data stream from the CAN controller toCAN bus compliant levels. An example of a CAN transceiver is Model No.TJA1055 or Model No. TJA1044 both available from NXP Semiconductors N.V.headquartered in Eindhoven, Netherlands, respectively described inProduct data sheets (document Identifier TJA1055, date of release: 6Dec. 2013) entitled: “TJA1055 Enhanced fault-tolerant CANtransceiver—Rev. 5-6 Dec. 2013—Product data sheet”, and Product datasheets (document Identifier TJA1055, date of release: 6 Dec. 2013)entitled: “TJA1044 High-speed CAN transceiver with Standby mode—Rev.4—10 Jul. 2015—Product data sheet”, which are both incorporated in theirentirety for all purposes as if fully set forth herein.

Another example of a CAN Transceiver is Model No. SN65HVD234D availablefrom Texas Instruments Incorporated (Headquartered in Dallas, Tex.,U.S.A.), described in Datasheet SLLS557G (NOVEMBER 2002—REVISED JANUARY2015), entitled: “SN65HVD23x 3.3-V CAN Bus Transceivers”, which isincorporated in its entirety for all purposes as if fully set forthherein. An example of a CAN controller is Model No. STM32F105Vcavailable from STMicroelectronics NV described in Datasheet DoclD15724Rev. 9, published September 2015 and entitled: “STM32F105xxSTM32F107xx”, which is incorporated in its entirety for all purposes asif fully set forth herein, which is part of the STM32F105xx connectivityline family that incorporates the high-performance ARM®Cortex®-M3 32-bitRISC core operating at a 72 MHz frequency, high-speed embedded memories(Flash memory up to 256 Kbytes and SRAM 64 Kbytes), and an extensiverange of enhanced I/Os and peripherals connected to two APB buses. Alldevices offer two 12-bit ADCs, four general-purpose 16-bit timers plus aPWM timer, as well as standard and advanced communication interfaces: upto two I2Cs, three SPIs, two I2Ss, five USARTs, an USB OTG FS and twoCANs.

A Controller Area Network (CAN) transceiver is disclosed in U.S. Pat.No. 9,471,528 to Muth entitled: “Controller area network (CAN)transceiver and method for operating a CAN transceiver”, which isincorporated in its entirety for all purposes as if fully set forthherein. The CAN transceiver includes a CAN bus interface, a TXDinterface, an RXD interface, a transmitter connected between the TXDinterface and the CAN bus interface, a receiver connected between theRXD interface and the CAN bus interface, a traffic control systemconnected between the CAN bus interface, the TXD interface, and the RXDinterface. The traffic control system detects the presence of CANFlexible Data-rate (FD) traffic on the CAN bus interface and if thetraffic control system detects the presence of CAN FD traffic on the CANbus interface, the traffic controls system changes an operating state ofthe transceiver.

Embodiments of a device and method are disclosed in U.S. Pat. No.9,330,045 to Muth et al. entitled: “Controller area network (CAN) deviceand method for controlling CAN traffic”, which is incorporated in itsentirety for all purposes as if fully set forth herein. In anembodiment, a CAN device is disclosed. The CAN device includes a TXDinput interface, a TXD output interface, an RXD input interface, an RXDoutput interface, and a traffic control system connected between the TXDinput and output interfaces and between the RXD input and outputinterfaces. The traffic control system is configured to detect thepresence of CAN Flexible Data-rate (FD) traffic on the RXD inputinterface and if the traffic control system detects the presence of CANFD traffic on the RXD input interface, disconnect the RXD inputinterface from the RXD output interface and disconnect the TXD inputinterface from the TXD output interface.

A network node is disclosed in U.S. Pat. No. 9,280,501 to Hopfnerentitled: “Compatible network node, in particular, for can bus systems”,which is incorporated in its entirety for all purposes as if fully setforth herein. The node including a device, in particular, an errordetection logic, which is deactivated if it is detected that a signalaccording to a first protocol or a first version of a first protocol isreceived, and which is not deactivated if it is detected that a signalaccording to a second, different protocol or a second, different versionof the first protocol is received.

Controller Area Network (CAN) communications apparatus and methods arepresented in U.S. Pat. No. 9,652,423 to Monroe et al. entitled: “CAN andflexible data rate CAN node apparatus and methods for mixed bus CAN FDcommunications”, which is incorporated in its entirety for all purposesas if fully set forth herein. The apparatus and methods are for CANflexible data rate (CAN FD) communications in a mixed CAN network withCAN FD nodes and one or more non-FD CAN nodes, in which a CAN FD nodewishing to transmit CAN FD frames sends a first predefined messagerequesting the non-FD CAN nodes to disable their transmitters beforetransmitting the CAN FD frames, and thereafter sends a second predefinedmessage or a predefined signal to return the non-FD CAN nodes to normaloperation.

Each node is able to send and receive messages, but not simultaneously.A message or Frame consists primarily of the ID (identifier), whichrepresents the priority of the message, and up to eight data bytes. ACRC, acknowledge slot [ACK] and other overhead are also part of themessage. The improved CAN FD extends the length of the data section toup to 64 bytes per frame. The message is transmitted serially onto thebus using a non-return-to-zero (NRZ) format and may be received by allnodes. The devices that are connected by a CAN network are typicallysensors, actuators, and other control devices. These devices areconnected to the bus through a host processor, a CAN controller, and aCAN transceiver. A terminating bias circuit is power and ground providedtogether with the data signaling in order to provide electrical bias andtermination at each end of each bus segment to suppress reflections.

CAN data transmission uses a lossless bit-wise arbitration method ofcontention resolution. This arbitration method requires all nodes on theCAN network to be synchronized to sample every bit on the CAN network atthe same time. While some call CAN synchronous, the data is transmittedwithout a clock signal in an asynchronous format. The CAN specificationsuse the terms “dominant” bits and “recessive” bits where dominant is alogical ‘0’ (actively driven to a voltage by the transmitter) andrecessive is a logical ‘1’ (passively returned to a voltage by aresistor). The idle state is represented by the recessive level (Logical1). If one node transmits a dominant bit and another node transmits arecessive bit, then there is a collision and the dominant bit “wins”.This means there is no delay to the higher-priority message, and thenode transmitting the lower priority message automatically attempts tore-transmit six bit clocks after the end of the dominant message. Thismakes CAN very suitable as a real time prioritized communicationssystem.

The exact voltages for a logical level ‘0’ or ‘1’ depend on the physicallayer used, but the basic principle of CAN requires that each nodelisten to the data on the CAN network including the data that thetransmitting node is transmitting. If a logical 1 is transmitted by alltransmitting nodes at the same time, then a logical 1 is seen by all ofthe nodes, including both the transmitting node(s) and receivingnode(s). If a logical 0 is transmitted by all transmitting node(s) atthe same time, then a logical 0 is seen by all nodes. If a logical 0 isbeing transmitted by one or more nodes, and a logical 1 is beingtransmitted by one or more nodes, then a logical 0 is seen by all nodesincluding the node(s) transmitting the logical 1. When a node transmitsa logical 1 but sees a logical 0, it realizes that there is a contentionand it quits transmitting. By using this process, any node thattransmits a logical 1 when another node transmits a logical 0 “dropsout” or loses the arbitration. A node that loses arbitration re-queuesits message for later transmission and the CAN frame bit-streamcontinues without error until only one node is left transmitting. Thismeans that the node that transmits the first 1, loses arbitration. Sincethe 11 (or 29 for CAN 2.0B) bit identifier is transmitted by all nodesat the start of the CAN frame, the node with the lowest identifiertransmits more zeros at the start of the frame, and that is the nodethat wins the arbitration or has the highest priority.

The CAN protocol, like many networking protocols, can be decomposed intothe following abstraction layers—Application layer, Object layer(including Message filtering and Message and status handling), andTransfer layer.

Most of the CAN standard applies to the transfer layer. The transferlayer receives messages from the physical layer and transmits thosemessages to the object layer. The transfer layer is responsible for bittiming and synchronization, message framing, arbitration,acknowledgement, error detection and signaling, and fault confinement.It performs Fault Confinement, Error Detection, Message Validation,Acknowledgement, Arbitration, Message Framing, Transfer Rate and Timing,and Information Routing.

The mechanical aspects of the physical layer (connector type and number,colors, labels, pin-outs) are not specified. As a result, an automotiveECU will typically have a particular—often custom—connector with varioussorts of cables, of which two are the CAN bus lines. Nonetheless,several de facto standards for mechanical implementation have emerged,the most common being the 9-pin D-sub type male connector with thefollowing pin-out: pin 2: CAN-Low (CAN−); pin 3: GND (Ground); pin 7:CAN-High (CAN+); and pin 9: CAN V+(Power). This de facto mechanicalstandard for CAN could be implemented with the node having both male andfemale 9-pin D-sub connectors electrically wired to each other inparallel within the node. Bus power is fed to a node's male connectorand the bus draws power from the node's female connector. This followsthe electrical engineering convention that power sources are terminatedat female connectors. Adoption of this standard avoids the need tofabricate custom splitters to connect two sets of bus wires to a singleD connector at each node. Such nonstandard (custom) wire harnesses(splitters) that join conductors outside the node, reduce busreliability, eliminate cable interchangeability, reduce compatibility ofwiring harnesses, and increase cost.

Noise immunity on ISO 11898-2:2003 is achieved by maintaining thedifferential impedance of the bus at a low level with low-valueresistors (120 ohms) at each end of the bus. However, when dormant, alow-impedance bus such as CAN draws more current (and power) than othervoltage-based signaling buses. On CAN bus systems, balanced lineoperation, where current in one signal line is exactly balanced bycurrent in the opposite direction in the other signal provides anindependent, stable 0 V reference for the receivers. Best practicedetermines that CAN bus balanced pair signals be carried in twisted pairwires in a shielded cable to minimize RF emission and reduceinterference susceptibility in the already noisy RF environment of anautomobile. ISO 11898-2 provides some immunity to common mode voltagebetween transmitter and receiver by having a ‘0’ V rail running alongthe bus to maintain a high degree of voltage association between thenodes. Also, in the de facto mechanical configuration mentioned above, asupply rail is included to distribute power to each of the transceivernodes. The design provides a common supply for all the transceivers. Theactual voltage to be applied by the bus and which nodes apply to it areapplication-specific and not formally specified. Common practice nodedesign provides each node with transceivers which are optically isolatedfrom their node host and derive a 5 V linearly regulated supply voltagefor the transceivers from the universal supply rail provided by the bus.This usually allows operating margin on the supply rail sufficient toallow interoperability across many node types. Typical values of supplyvoltage on such networks are 7 to 30 V. However, the lack of a formalstandard means that system designers are responsible for supply railcompatibility.

ISO 11898-2 describes the electrical implementation formed from amulti-dropped single-ended balanced line configuration with resistortermination at each end of the bus. In this configuration, a dominantstate is asserted by one or more transmitters switching the CAN- tosupply 0 V and (simultaneously) switching CAN+ to the +5 V bus voltagethereby forming a current path through the resistors that terminate thebus. As such, the terminating resistors form an essential component ofthe signaling system and are included not just to limit wave reflectionat high frequency. During a recessive state, the signal lines andresistor(s) remain in a high impedances state with respect to bothrails. Voltages on both CAN+ and CAN− tend (weakly) towards ½ railvoltage. A recessive state is only present on the bus when none of thetransmitters on the bus is asserting a dominant state. During a dominantstate the signal lines and resistor(s) move to a low impedance statewith respect to the rails so that current flows through the resistor.CAN+ voltage tends to +5 V and CAN− tends to 0 V. Irrespective of signalstate the signal lines are always in low impedance state with respect toone another by virtue of the terminating resistors at the end of thebus. Multiple access on CAN bus is achieved by the electrical logic ofthe system supporting just two states that are conceptually analogous toa ‘wired OR’ network.

The CAN is standardized in a standards set ISO 11898 entitled: “Roadvehicles—Controller area network (CAN)” that specifies physical anddatalink layer (levels 1 and 2 of the ISO/OSI model) of serialcommunication technology called Controller Area Network that supportsdistributed real-time control and multiplexing for use within roadvehicles

The standard ISO 11898-1:2015 entitled: “Part 1: Data link layer andphysical signalling” specifies the characteristics of setting up aninterchange of digital information between modules implementing the CANdata link layer. Controller area network is a serial communicationprotocol, which supports distributed real-time control and multiplexingfor use within road vehicles and other control applications. The ISO11898-1:2015 specifies the Classical CAN frame format and the newlyintroduced CAN Flexible Data Rate Frame format. The Classical CAN frameformat allows bit rates up to 1 Mbit/s and payloads up to 8 byte perframe. The Flexible Data Rate frame format allows bit rates higher than1 Mbit/s and payloads longer than 8 byte per frame. ISO 11898-1:2015describes the general architecture of CAN in terms of hierarchicallayers according to the ISO reference model for open systemsinterconnection (OSI) according to ISO/IEC 7498-1. The CAN data linklayer is specified according to ISO/IEC 8802-2 and ISO/IEC 8802-3. ISO11898-1:2015 contains detailed specifications of the following: logicallink control sub-layer; medium access control sub-layer; and physicalcoding sub-layer.

The standard ISO 11898-2:2003 entitled: “Part 2: High-speed mediumaccess unit” specifies the high-speed (transmission rates of up to 1Mbit/s) medium access unit (MAU), and some medium dependent interface(MDI) features (according to ISO 8802-3), which comprise the physicallayer of the controller area network (CAN): a serial communicationprotocol that supports distributed real-time control and multiplexingfor use within road vehicles.

The standard ISO 11898-3:2006 entitled: “Part 3: Low-speed,fault-tolerant, medium-dependent interface” specifies characteristics ofsetting up an interchange of digital information between electroniccontrol units of road vehicles equipped with the controller area network(CAN) at transmission rates above 40 kBit/s up to 125 kBit/s.

The standard ISO 11898-4:2004 entitled: “Part 4: Time-triggeredcommunication” specifies time-triggered communication in the controllerarea network (CAN): a serial communication protocol that supportsdistributed real-time control and multiplexing for use within roadvehicles. It is applicable to setting up a time-triggered interchange ofdigital information between electronic control units (ECU) of roadvehicles equipped with CAN, and specifies the frame synchronizationentity that coordinates the operation of both logical link and mediaaccess controls in accordance with ISO 11898-1, to provide thetime-triggered communication schedule.

The standard ISO 11898-5:2007 entitled: “Part 5: High-speed mediumaccess unit with low-power mode” specifies the CAN physical layer fortransmission rates up to 1 Mbit/s for use within road vehicles. Itdescribes the medium access unit functions as well as some mediumdependent interface features according to ISO 8802-2. ISO 11898-5:2007represents an extension of ISO 11898-2, dealing with new functionalityfor systems requiring low-power consumption features while there is noactive bus communication. Physical layer implementations according toISO 11898-5:2007 are compliant with all parameters of ISO 11898-2, butare defined differently within ISO 11898-5:2007. Implementationsaccording to ISO 11898-5:2007 and ISO 11898-2 are interoperable and canbe used at the same time within one network.

The standard ISO 11898-6:2013 entitled: “Part 6: High-speed mediumaccess unit with selective wake-up functionality” specifies thecontroller area network (CAN) physical layer for transmission rates upto 1 Mbit/s. It describes the medium access unit (MAU) functions. ISO11898-6:2013 represents an extension of ISO 11898-2 and ISO 11898-5,specifying a selective wake-up mechanism using configurable CAN frames.Physical layer implementations according to ISO 11898-6:2013 arecompliant with all parameters of ISO 11898-2 and ISO 11898-5.Implementations according to ISO 11898-6:2013, ISO 11898-2 and ISO11898-5 are interoperable and can be used at the same time within onenetwork.

The standard ISO 11992-1:2003 entitled: “Road vehicles—Interchange ofdigital information on electrical connections between towing and towedvehicles—Part 1: Physical and data-link layers” specifies theinterchange of digital information between road vehicles with a maximumauthorized total mass greater than 3 500 kg, and towed vehicles,including communication between towed vehicles in terms of parametersand requirements of the physical and data link layer of the electricalconnection used to connect the electrical and electronic systems. Italso includes conformance tests of the physical layer.

The standard ISO 11783-2:2012 entitled: “Tractors and machinery foragriculture and forestry—Serial control and communications datanetwork—Part 2: Physical layer” specifies a serial data network forcontrol and communications on forestry or agricultural tractors andmounted, semi-mounted, towed or self-propelled implements. Its purposeis to standardize the method and format of transfer of data betweensensors, actuators, control elements and information storage and displayunits, whether mounted on, or part of, the tractor or implement, and toprovide an open interconnect system for electronic systems used byagricultural and forestry equipment. ISO 11783-2:2012 defines anddescribes the network's 250 kbit/s, twisted, non-shielded, quad-cablephysical layer. ISO 11783-2 uses four unshielded twisted wires; two forCAN and two for terminating bias circuit (TBC) power and ground. Thisbus is used on agricultural tractors. It is intended to provideinterconnectivity between the tractor and any agricultural implementadhering to the standard.

The standard J1939/11_201209 entitled: “Physical Layer, 250 Kbps,Twisted Shielded Pair” defines a physical layer having a robust immunityto EMI and physical properties suitable for harsh environments. TheseSAE Recommended Practices are intended for light- and heavy-dutyvehicles on- or off-road as well as appropriate stationary applicationswhich use vehicle derived components (e.g., generator sets). Vehicles ofinterest include but are not limited to: on- and off-highway trucks andtheir trailers; construction equipment; and agricultural equipment andimplements.

The standard SAE J1939/15_201508 entitled: “Physical Layer, 250 Kbps,Un-Shielded Twisted Pair (UTP)” describes a physical layer utilizingUnshielded Twisted Pair (UTP) cable with extended stub lengths forflexibility in ECU placement and network topology. CAN controllers arenow available which support the newly introduced CAN Flexible Data RateFrame format (known as “CAN FD”). These controllers, when used on SAEJ1939-15 networks, must be restricted to use only the Classical Frameformat compliant to ISO 11898-1 (2003).

The standard SAE J2411_200002 entitled: “Single Wire Can Network forVehicle Applications” defines the Physical Layer and portions of theData Link Layer of the OSI model for data communications. In particular,this document specifies the physical layer requirements for any CarrierSense Multiple Access/Collision Resolution (CSMA/CR) data link whichoperates on a single wire medium to communicate among Electronic ControlUnits (ECU) on road vehicles. Requirements stated in this document willprovide a minimum standard level of performance to which all compatibleECUs and media shall be designed. This will assure full serial datacommunication among all connected devices regardless of the supplier.This document is to be referenced by the particular vehicle OEMComponent Technical Specification which describes any given ECU, inwhich the single wire data link controller and physical layer interfaceis located. Primarily, the performance of the physical layer isspecified in this document.

A specification for CAN FD (CAN with Flexible Data-Rate) version 1.0 wasreleased on Apr. 17, 2012 by Robert Bosch GmbH entitled: CAN withFlexible Data-Rate Specification Version 1.0), and is incorporated inits entirety for all purposes as if fully set forth herein. Thisspecification uses a different frame format that allows a different datalength as well as optionally switching to a faster bit rate after thearbitration is decided. CAN FD is compatible with existing CAN 2.0networks so new CAN FD devices can coexist on the same network withexisting CAN devices. CAN FD is further described in iCC 2013 CAN inAutomation articles by Florian Hatwich entitled: “Bit Time Requirementsfor CAN FD” and “Can with Flexible Data-Rate”, and in NationalInstruments article published Aug. 1, 2014 entitled: “Understanding CANwith Flexible Data-Rate (CAN FD)”, which are all incorporated in theirentirety for all purposes as if fully set forth herein. In one example,the CAN FD interface is based on, compatible with, or uses, theSPC57EM80 controller device available from STMicroelectronics describedin an Application Note AN4389 (document number DocD025493 Rev 2)published 2014 entitled: “SPC57472/SPC57EM80 Getting Started”, which isincorporated in its entirety for all purposes as if fully set forthherein. Further, a CAN FD transceiver may be based on, compatible with,or use, transceiver model MCP2561/2FD available from MicrochipTechnology Inc., described in a data sheet DS20005284A published 2014[ISBN—978-1-63276-020-3] entitled: “MCP2561/2FD—High-Speed CAN FlexibleData Rate Transceiver”, which is incorporated in its entirety for allpurposes as if fully set forth herein.

A fraud detection method for use in an in-vehicle network systemincluding a plurality of electronic control units that communicate withone another via a bus in accordance with Controller Area Network (CAN)protocol is disclosed in U.S. Patent Application Publication No.2016/020519 to Kishikawa et al. entitled: “Method for detectingfraudulent frame sent over an in-vehicle network system”, which isincorporated in its entirety for all purposes as if fully set forthherein. A fraud detection method for use in an in-vehicle network systemincluding a plurality of electronic control units that communicate withone another via a bus in accordance with Controller Area Network (CAN)protocol is provided. The method includes receiving at least one dataframe sent to the bus, verifying a specific identifier in the receiveddata frame only if the received data frame does not follow apredetermined rule regarding a transmission period and a state of avehicle having the in-vehicle network system mounted therein is apredetermined state, detecting the received data frame as anauthenticated data frame if the verification is successful, anddetecting the received data frame as a fraudulent data frame if theverification fails.

CAN frame. A data frame having a standard ID format defined by the CANprotocol is illustrated in FIG. 2. The data frame includes an SOF (StartOf Frame) field, an ID field, an RTR (Remote Transmission Request)field, an IDE (identifier Extension) field, a reservation bit “r” a DLC(Data Length Code) field, a data field, a CRC (Cyclic Redundancy Check)sequence field, a CRC delimiter field “DEL”, an ACK (Acknowledgement)slot field, an ACK delimiter field “DEL”, and an EOF (End Of Frame)field.

The SOF field is formed from one dominant bit. When the bus is idle, thestate of the bus is recessive. By changing the state of the bus fromrecessive to dominant using SOF, the notice of start of frametransmission is given. The ID field is an 11-bit field. The ID fieldincludes an ID (a message ID) that is a value indicating the type ofdata. In order to perform communication arbitration using the ID field,the design is such that if a plurality of nodes simultaneously starttransmission, a frame having a lower ID value has a higher priority. RTRis a value for distinguishing a data frame from a remote frame. In dataframes, the RTR field is formed from one dominant bit. Each of IDE and“r” is formed from one dominant bit. DLC is of 4 bits. DLC indicates thelength of the data field. Note that IDE, “r”, and DLC are collectivelyreferred to as a “control field”. The data field indicates the data tobe transmitted, where the maximum length of the data field is 64 bits.The length can be controlled to 8 to 64 bits (multiple of 8 bits). Thespecification of data to be transmitted is not defined by the CANprotocol and is defined by the in-vehicle network system 10.Accordingly, the specification of the data depends on, for example, thetype of vehicle and the manufacturer (the maker). The CRC sequence fieldis a 15-bit field. The CRC sequence is calculated using the transmittedvalues of SOF, the ID field, the control field, and the data field. TheCRC delimiter is formed from one recessive bit. The CRC delimiter is adelimiter symbol that indicates termination of the CRC sequence. Notethat the CRC sequence field and the CRC delimiter field are collectivelyreferred to as a “CRC field”.

The ACK slot field is a 1-bit field. The sender node sets the ACK slotto recessive and transmits data. If a receiver node successfullyreceives the data up to the CRC sequence, the receiver node sets the ACKslot to dominant and sends the data. The dominant has a priority overthe recessive. Accordingly, if the ACK slot is dominant aftertransmission, the sender node can be aware that any one of the receivernodes has successfully received the data. The ACK delimiter is formedfrom one recessive hit. The ACK delimiter is a delimiter symbol thatindicates termination of ACK. The EOF field is formed from 7 recessivebits. EOF indicates termination of the data frame.

ISO 15765-2. ISO-TP (Transport Layer) is described in ISO 15765-2:2004standard (First Edition 2004-10-15) entitled: “Road vehicles—Diagnosticson Controller Area Networks (CAN)—Part 2: Network layer services”, whichis incorporated in its entirety for all purposes as if fully set forthherein. ISO-TP specifies a transport protocol and network layer servicestailored to meet the requirements of CAN-based vehicle network systemson controller area networks as specified in ISO 11898-1. It has beendefined in accordance with the diagnostic services established in ISO14229-1 and ISO 15031-5 but is not limited to use with them and is alsocompatible with most other communication needs for in-vehicle networks.ISO 11898-1 specifies variable length CAN frames with a maximum payloadsize dependent on the protocol device used. A CLASSICAL CAN protocoldevice can transmit/receive frames with payload sizes ranging from 0bytes to 8 bytes per frame. A CAN FD (flexible data rate) protocoldevice can transmit/receive frames with payload sizes from 0 bytes to 64bytes. A CAN FD protocol device is also capable of transmittingreceiving CLASSICAL CAN frames.

In the OSI Model, ISO-TP covers the layer 3 (network layer) and 4(transport layer). The most common application for ISO-TP is thetransfer of diagnostic messages with OBD-2 equipped vehicles usingKWP2000 and UDS, but is used broadly in other application-specific CANimplementations. ISO-TP can be operated with its own addressing asso-called Extended Addressing or without address using only the CAN ID(so-called Normal Addressing). Extended addressing uses the first databyte of each frame as an additional element of the address, reducing theapplication payload by one byte. For clarity the protocol descriptionbelow is based on Normal Addressing with eight byte CAN frames. Intotal, six types of addressing are allowed by the ISO 15765-2 Protocol.ISO-TP prepends one or more metadata bytes to the payload data in theeight byte CAN frame, reducing the payload to seven or fewer bytes perframe. The metadata is called the Protocol Control Information, or PCI.The PCI is one, two or three bytes. The initial field is four bitsindicating the frame type, and implicitly describing the PCI length.

The diagnostic communication over controller area network (DoCAN)protocol supports the standardized service primitive interface asspecified in ISO 14229-2 (UDS). ISO) 15765-2 standard provides thetransport protocol and network layer services to support differentapplication-layer implementations such as enhanced vehicle diagnostics(emissions-related system diagnostics beyond legislated functionality,non-emissions-related system diagnostics), emissions-related on-boarddiagnostics (OBD) as specified in ISO 15031, world-wide harmonizedon-board diagnostics (WWH-OBD) as specified in ISO 27145, and end oflife activation on on-board pyrotechnic devices (ISO 26021). Thetransport protocol specifies an unconfirmed communication.

LIN. LIN (Local Interconnect Network) is a serial network protocol usedfor communication between components in vehicles. The LIN communicationmay be based on, compatible with, or is according to, ISO 9141, and isdescribed in “LIN Specification Package—Revision 2.2A” by the LINConsortium (dated Dec. 31, 2010), which is incorporated in its entiretyfor all purposes as if fully set forth herein. The LIN standard isfurther standardized as part of ISO 17987-1 to 17987-7 standards. LINmay be used also over the vehicle's battery power-line with a specialDC-LIN transceiver. LIN is a broadcast serial network comprising 16nodes (one master and typically up to 15 slaves). All messages areinitiated by the master with at most one slave replying to a givenmessage identifier. The master node can also act as a slave by replyingto its own messages, and since all communications are initiated by themaster it is not necessary to implement a collision detection. Themaster and slaves are typically microcontrollers, but may be implementedin specialized hardware or ASICs in order to save cost, space, or power.Current uses combine the low-cost efficiency of LIN and simple sensorsto create small networks that can be connected by a backbone network.(i.e., CAN in cars).

The LIN bus is an inexpensive serial communications protocol, whicheffectively supports remote application within a car's network, and isparticularly intended for mechatronic nodes in distributed automotiveapplications, but is equally suited to industrial applications. Theprotocol's main features are single master, up to 16 slaves (i.e. no busarbitration), Slave Node Position Detection (SNPD) that allows nodeaddress assignment after power-up, Single wire communications up to 19.2kbit/s @ 40 meter bus length (in the LIN specification 2.2 the speed upto 20 kbit/s), Guaranteed latency times, Variable length of data frame(2, 4 and 8 byte), Configuration flexibility, Multi-cast reception withtime synchronization, without crystals or ceramic resonators, Datachecksum and error detection, Detection of defective nodes, Low costsilicon implementation based on standard UART/SCI hardware, Enabler forhierarchical networks, and Operating voltage of 12 V. LIN is furtherdescribed in U.S. Pat. No. 7,091,876 to Steger entitled: “Method forAddressing the Users of a Bus System by Means of Identification Flows”,which is incorporated in its entirety for all purposes as if fully setforth herein.

Data is transferred across the bus in fixed form messages of selectablelengths. The master task transmits a header that consists of a breaksignal followed by synchronization and identifier fields. The slavesrespond with a data frame that consists of between 2, 4 and 8 data bytesplus 3 bytes of control information. The LIN uses Unconditional Frames,Event-triggered Frames, Sporadic Frames, Diagnostic Frames, User-DefinedFrames, and Reserved Frames.

Unconditional Frames always carry signals and their identifiers are inthe range 0 to 59 (0x00 to 0x3b) and all subscribers of theunconditional frame shall receive the frame and make it available to theapplication (assuming no errors were detected), and Event-triggeredFrame, to increase the responsiveness of the LIN cluster withoutassigning too much of the bus bandwidth to the polling of multiple slavenodes with seldom occurring events. The first data byte of the carriedunconditional frame shall be equal to a protected identifier assigned toan event-triggered frame. A slave shall reply with an associatedunconditional frame only if its data value has changed. If none of theslave tasks responds to the header, the rest of the frame slot is silentand the header is ignored. If more than one slave task responds to theheader in the same frame slot a collision will occur, and the master hasto resolve the collision by requesting all associated unconditionalframes before requesting the event-triggered frame again. Sporadic Frameis transmitted by the master as required, so a collision cannot occur.The header of a sporadic frame shall only be sent in its associatedframe slot when the master task knows that a signal carried in the framehas been updated. The publisher of the sporadic frame shall alwaysprovide the response to the header. Diagnostic Frame always carrydiagnostic or configuration data and they always contain eight databytes. The identifier is either 60 (0x3C), called master request frame,or 61(0x3D), called slave response frame. Before generating the headerof a diagnostic frame, the master task asks its diagnostic module if itshall be sent or if the bus shall be silent. The slave tasks publish andsubscribe to the response according to their diagnostic module.User-Defined Frame carry any kind of information. Their identifier is 62(0x3E). The header of a user-defined frame is usually transmitted when aframe slot allocated to the frame is processed. Reserved Frame are notbe used in a LIN 2.0 cluster, and their identifier is 63 (0x3F).

The LIN specification was designed to allow very cheap hardware-nodesbeing used within a network. The LIN specification is based on ISO9141:1989 standard entitled: “Road vehicles—Diagnosticsystems—Requirements for interchange of digital information” thatSpecifies the requirements for setting up the interchange of digitalinformation between on-board Electronic Control Units (ECUs) of roadvehicles and suitable diagnostic testers. This communication isestablished in order to facilitate inspection, test diagnosis andadjustment of vehicles, systems and ECUs. It does not apply whensystem-specific diagnostic test equipment is used. The LIN specificationis further based on ISO 9141-2:1994 standard entitled: “Roadvehicles—Diagnostic systems—Part 2: GARB requirements for interchange ofdigital information” that involves vehicles with nominal 12 V supplyvoltage, describes a subset of ISO 9141:1989, and specifies therequirements for setting-up the interchange of digital informationbetween on-board emission-related electronic control units of roadvehicles and the SAE OBD II scan tool as specified in SAE J1978. It is alow-cost, single-wire network, where microcontrollers with either UARTcapability or dedicated LIN hardware are used. The microcontrollergenerates all needed LIN data by software and is connected to the LINnetwork via a LIN transceiver (simply speaking, a level shifter withsome add-ons). Working as a LIN node is only part of the possiblefunctionality. The LIN hardware may include this transceiver and worksas a pure LIN node without added functionality. As LIN Slave nodesshould be as cheap as possible, they may generate their internal clocksby using RC oscillators instead of crystal oscillators (quartz or aceramic). To ensure the baud rate-stability within one LIN frame, theSYNC field within the header is used. An example of a LIN transceiver isIC Model No. 33689D available from Freescale Semiconductor, Inc.described in a data-sheet Document Number MC33689 Rev. 8.0 (datedSeptember 2012) entitled: “System Basis Chip with LIN Transceiver”,which is incorporated in its entirety for all purposes as if fully setforth herein.

The LIN-Master uses one or more predefined scheduling tables to startthe sending and receiving to the LIN bus. These scheduling tablescontain at least the relative timing, where the message sending isinitiated. One LIN Frame consists of the two parts header and response.The header is always sent by the LIN Master, while the response is sentby either one dedicated LIN-Slave or the LIN master itself. Transmitteddata within the LIN is transmitted serially as eight-bit data bytes withone start & stop-bit and no parity. Bit rates vary within the range of 1kbit/s to 20 kbit/s. Data on the bus is divided into recessive (logicalHIGH) and dominant (logical LOW). The time normal is considered by theLIN Masters stable clock source, the smallest entity is one bit time (52μs @ 19.2 kbit/s).

Two bus states—Sleep-mode and active—are used within the LIN protocol.While data is on the bus, all LIN-nodes are requested to be in activestate. After a specified timeout, the nodes enter Sleep mode and will bereleased back to active state by a WAKEUP frame. This frame may be sentby any node requesting activity on the bus, either the LIN Masterfollowing its internal schedule, or one of the attached LIN Slaves beingactivated by its internal software application. After all nodes areawakened, the Master continues to schedule the next Identifier.

MOST. MOST (Media Oriented Systems Transport) is a high-speed multimedianetwork technology optimized for use in automotive applications, and maybe used for applications inside or outside the car. The serial MOST bususes a ring topology and synchronous data communication to transportaudio, video, voice and data signals via plastic optical fiber (POF)(MOST25, MOST150) or electrical conductor (MOST50, MOST150) physicallayers. The MOST specification defines the physical and the data linklayer as well as all seven layers of the ISO/OSI-Model of datacommunication. Standardized interfaces simplify the MOST protocolintegration in multimedia devices. For the system developer, MOST isprimarily a protocol definition. It provides the user with astandardized interface (API) to access device functionality, and thecommunication functionality is provided by driver software known as MOSTNetwork Services. MOST Network Services include Basic Layer SystemServices (Layer 3, 4, 5) and Application Socket Services (Layer 6). Theyprocess the MOST protocol between a MOST Network Interface Controller(NIC), which is based on the physical layer, and the API (Layer 7).

A MOST network is able to manage up to 64 MOST devices in a ringconfiguration. Plug and play functionality allows MOST devices to beeasily attached and removed. MOST networks can also be set up in virtualstar network or other topologies. Safety critical applications useredundant double ring configurations. In a MOST network, one device isdesignated the timing master, used to continuously supply the ring withMOST frames. A preamble is sent at the beginning of the frame transfer.The other devices, known as timing followers, use the preamble forsynchronization. Encoding based on synchronous transfer allows constantpost-sync for the timing followers.

MOST25 provides a bandwidth of approximately 23 megabaud for streaming(synchronous) as well as package (asynchronous) data transfer over anoptical physical layer. It is separated into 60 physical channels. Theuser can select and configure the channels into groups of four byteseach. MOST25 provides many services and methods for the allocation (anddeallocation) of physical channels. MOST25 supports up to 15uncompressed stereo audio channels with CD-quality sound or up to 15MPEG-1 channels for audio/video transfer, each of which uses four Bytes(four physical channels). MOST also provides a channel for transferringcontrol information. The system frequency of 44.1 kHz allows a bandwidthof 705.6 kbit/s, enabling 2670 control messages per second to betransferred. Control messages are used to configure MOST devices andconfigure synchronous and asynchronous data transfer. The systemfrequency closely follows the CD standard. Reference data can also betransferred via the control channel. Some limitations restrict MOST25'seffective data transfer rate to about 10 kB/s. Because of the protocoloverhead, the application can use only 11 of 32 bytes at segmentedtransfer and a MOST node can only use one third of the control channelbandwidth at any time.

MOST50 doubles the bandwidth of a MOST25 system and increases the framelength to 1024 bits. The three established channels (control messagechannel, streaming data channel, and packet data channel) of MOST25remain the same, but the length of the control channel and thesectioning between the synchronous and asynchronous channels areflexible. Although MOST50 is specified to support both optical andelectrical physical layers, the available MOST50 Intelligent NetworkInterface Controllers (INICs) only support electrical data transfer viaUnshielded Twisted Pair (UTP).

MOST150 was introduced in October 2007 and provides a physical layer toimplement Ethernet in automobiles. It increases the frame length up to3072 bits, which is about 6 times the bandwidth of MOST25. It alsointegrates an Ethernet channel with adjustable bandwidth in addition tothe three established channels (control message channel, streaming datachannel, and packet data channel) of the other grades of MOST. MOST150also permits isochronous transfer on the synchronous channel. Althoughthe transfer of synchronous data requires a frequency other than the onespecified by the MOST frame rate, it is also possible with MOST150.MOST150's advanced functions and enhanced bandwidth will enable amultiplex network infrastructure capable of transmitting all forms ofinfotainment data, including video, throughout an automobile. Theoptical transmission layer uses Plastic Optical Fibers (POF) with a corediameter of 1 mm as transmission medium, in combination with lightemitting diodes (LEDs) in the red wavelength range as transmitters.MOST25 only uses an optical Physical Layer. MOST50 and MOST150 supportboth optical and electrical Physical Layers.

The MOST protocol is described in a book published 2011 by FranzisVerlag Gmbh [ISBN—978-3-645-65061-8] edited by Prof. Dr. Ing. AndreasGrzemba entitled: “MOST—The Automotive Multimedia Network—From MOST25 toMOST 150”, in MOST Dynamic Specification by MOST Cooperation Rev. 3.0.2dated October 2012 entitled: “MOST—Multimedia and Control NetworkingTechnology”, and in MOST Specification Rev. 3.0 E2 dated July 2010 byMOST Cooperation, which are all incorporated in their entirety for allpurposes as if fully set forth herein.

MOST Interfacing may use a MOST transceiver, such as IC model No.OS81118 available from Microchip Technology Incorporated (headquarteredin Chandler, Ariz., U.S.A.) and described in a data sheet DS00001935Apublished 2015 by Microchip Technology Incorporated entitled: “MOST150INIC with USB 2.0 Device Port”, or IC model No. OS8104A also availablefrom Microchip Technology Incorporated and described in a data sheetPFL_OS8104A_V01_00_XX-4.fm published August 2007 by Microchip TechnologyIncorporated entitled: “MOST Network Interface Controller”, which areboth incorporated in their entirety for all purposes as if fully setforth herein.

FlexRay. FlexRay™ is an automotive network communications protocoldeveloped by the FlexRay Consortium to govern on-board automotivecomputing. The FlexRay consortium disbanded in 2009, but the FlexRaystandard is described in a set of ISO standards, ISO 17458 entitled:“Road vehicles—FlexRay communications system”, including ISO17458-1:2013 standard entitled: “Part 1: General information and usecase definition”, ISO 17458-2:2013 standard entitled: “Part 2: Data linklayer specification”, ISO 17458-3:2013 standard entitled: “Part 3: Datalink layer conformance test specification”, ISO 17458-4:2013 standardentitled: “Part 4: Electrical physical layer specification”, and ISO17458-5:2013 standard entitled: “Part 5: Electrical physical layerconformance test specification”.

FlexRay supports high data rates, up to 10 Mbit/s, explicitly supportsboth star and “party line” bus topologies, and can have two independentdata channels for fault-tolerance (communication can continue withreduced bandwidth if one channel is inoperative). The bus operates on atime cycle, divided into two parts: the static segment and the dynamicsegment. The static segment is pre-allocated into slices for individualcommunication types, providing a stronger real-time guarantee than itspredecessor CAN. The dynamic segment operates more like CAN, with nodestaking control of the bus as available, allowing event-triggeredbehavior. FlexRay specification Version 3.0.1 is described in FlexRayconsortium October 2010 publication entitled: “FlexRay CommunicationsSystem—Protocol Specification—Version 3.0.1”, which is incorporated inits entirety for all purposes as if fully set forth herein. The FlexRayphysical layer is described in Carl Hanser Verlag Gmbh 2010 publication(Automotive 2010) by Lorenz, Steffen entitled: “The FlexRay ElectricalPhysical Layer Evolution”, and in National Instruments CorporationTechnical Overview Publication (Aug. 21, 2009) entitled: “FlexRayAutomotive Communication Bus Overview”, which are both incorporated intheir entirety for all purposes as if fully set forth herein.

FlexRay system consists of a bus and processors (Electronic controlunit, or ECUs), where each ECU has an independent clock. The clock driftmust be not more than 0.15% from the reference clock, so the differencebetween the slowest and the fastest clock in the system is no greaterthan 0.3%. At each time, only one ECU writes to the bus, and each bit tobe sent is held on the bus for 8 sample clock cycles. The receiver keepsa buffer of the last 5 samples, and uses the majority of the last 5samples as the input signal. Single-cycle transmission errors may affectresults near the boundary of the bits, but will not affect cycles in themiddle of the 8-cycle region. The value of the bit is sampled in themiddle of the 8-bit region. The errors are moved to the extreme cycles,and the clock is synchronized frequently enough for the drift to besmall (Drift is smaller than 1 cycle per 300 cycles, and duringtransmission the clock is synchronized more than once every 300 cycles).An example of a FlexRay transceiver is model TJA1080A available from NXPSemiconductors N.V. headquartered in Eindhoven, Netherlands, describedin Product data sheet (document Identifier TJA1080A, date of release: 28Nov. 2012) entitled: “TJA1080A FlexRay Transceiver—Rev. 6-28 Nov.2012—Product data sheet”, which is incorporated in its entirety for allpurposes as if fully set forth herein.

Further, the vehicular communication system employed may be used so thatvehicles may communicate and exchange information with other vehiclesand with roadside units, may allow for cooperation and may be effectivein increasing safety such as sharing safety information, safetywarnings, as well as traffic information, such as to avoid trafficcongestion. In safety applications, vehicles that discover an imminentdanger or obstacle in the road may inform other vehicles directly, viaother vehicles serving as repeaters, or via roadside units. Further, thesystem may help in deciding right to pass first at intersections, andmay provide alerts or warning about entering intersections, departinghighways, discovery of obstacles, and lane change warnings, as well asreporting accidents and other activities in the road. The system may beused for traffic management, allowing for easy and optimal traffic flowcontrol, in particular in the case of specific situations such as hotpursuits and bad weather. The traffic management may be in the form ofvariable speed limits, adaptable traffic lights, traffic intersectioncontrol, and accommodating emergency vehicles such as ambulances, firetrucks and police cars.

The vehicular communication system may further be used to assist thedrivers, such as helping with parking a vehicle, cruise control, lanekeeping, and road sign recognition. Similarly, better policing andenforcement may be obtained by using the system for surveillance, speedlimit warning, restricted entries, and pull-over commands. The systemmay be integrated with pricing and payment systems such as tollcollection, pricing management, and parking payments. The system mayfurther be used for navigation and route optimization, as well asproviding travel-related information such as maps, business location,gas stations, and car service locations. Similarly, the system may beused for emergency warning system for vehicles, cooperative adaptivecruise control, cooperative forward collision warning, intersectioncollision avoidance, approaching emergency vehicle warning (Blue Waves),vehicle safety inspection, transit or emergency vehicle signal priority,electronic parking payments, commercial vehicle clearance and safetyinspections, in-vehicle signing, rollover warning, probe datacollection, highway-rail intersection warning, and electronic tollcollection.

OBD. On-Board Diagnostics (OBD) refers to a vehicle's self-diagnosticand reporting capability. OBD systems give the vehicle owner or repairtechnician access to the status of the various vehicle subsystems.Modern OBD implementations use a standardized digital communicationsport to provide real-time data in addition to a standardized series ofdiagnostic trouble codes, or DTCs, which allow one to rapidly identifyand remedy malfunctions within the vehicle. Keyword Protocol 2000,abbreviated KWP2000, is a communications protocol used for on-boardvehicle diagnostics systems (OBD). This protocol covers the applicationlayer in the OSI model of computer networking. KWP2000 also covers thesession layer in the OSI model, in terms of starting, maintaining andterminating a communications session, and the protocol is standardizedby International Organization for Standardization as ISO 14230.

One underlying physical layer used for KWP2000 is identical to ISO 9141,with bidirectional serial communication on a single line called theK-line. In addition, there is an optional L-line for wakeup. The datarate is between 1.2 and 10.4 kilobaud, and a message may contain up to255 bytes in the data field. When implemented on a K-line physicallayer, KWP2000 requires special wakeup sequences: 5-baud wakeup andfast-initialization. Both of these wakeup methods require timingcritical manipulation of the K-line signal, and are therefore not easyto reproduce without custom software. KWP2000 is also compatible on ISO11898 (Controller Area Network) supporting higher data rates of up to 1Mbit/s. CAN is becoming an increasingly popular alternative to K-linebecause the CAN bus is usually present in modern-day vehicles and thusremoving the need to install an additional physical cable. Using KWP2000on CAN with ISO 15765 Transport/Network layers is most common. Alsousing KWP2000 on CAN does not require the special wakeup functionality.

KWP2000 can be implemented on CAN using just the service layer andsession layer (no header specifying length, source and target addressesis used and no checksum is used); or using all layers (header andchecksum are encapsulated within a CAN frame). However using all layersis overkill, as ISO 15765 provides its own Transport/Network layers.

ISO 14230-1:2012 entitled: “Road vehicles—Diagnostic communication overK-Line (DoK-Line)—Part 1: Physical layer”, which is incorporated in itsentirety for all purposes as if fully set forth herein, specifies thephysical layer, based on ISO 9141, on which the diagnostic services willbe implemented. It is based on the physical layer described in ISO9141-2, but expanded to allow for road vehicles with either 12 V DC or24 V DC voltage supply.

ISO 14230-2:2013 entitled: “Road vehicles—Diagnostic communication overK-Line (DoK-Line)—Part 2: Data link layer”, which is incorporated in itsentirety for all purposes as if fully set forth herein, specifies datalink layer services tailored to meet the requirements of UART-basedvehicle communication systems on K-Line as specified in ISO 14230-1. Ithas been defined in accordance with the diagnostic services establishedin ISO 14229-1 and ISO 15031-5, but is not limited to use with them, andis also compatible with most other communication needs for in-vehiclenetworks. The protocol specifies an unconfirmed communication. Thediagnostic communication over K-Line (DoK-Line) protocol supports thestandardized service primitive interface as specified in ISO 14229-2.ISO 14230-2:2013 provides the data link layer services to supportdifferent application layer implementations like: enhanced vehiclediagnostics (emissions-related system diagnostics beyond legislatedfunctionality, non-emissions-related system diagnostics);emissions-related OBD as specified in ISO 15031, SAE J1979-DA, and SAEJ2012-DA. In addition, ISO 14230-2:2013 clarifies the differences ininitialization for K-line protocols defined in ISO 9141 and ISO 14230.This is important since a server supports only one of the protocolsmentioned above and the client has to handle the coexistence of allprotocols during the protocol-determination procedure.

The application layer is described in ISO 14230-3:1999 entitled: “Roadvehicles—Diagnostic systems—Keyword Protocol 2000—Part 3: Applicationlayer”, and the requirements for emission-related systems are describedin ISO 14230-4:2000 entitled: “Road vehicles—Diagnostic systems—KeywordProtocol 2000—Part 4: Requirements for emission-related systems”, whichare both incorporated in their entirety for all purposes as if fully setforth herein.

Automotive Ethernet. Automotive Ethernet refers to the use of anEthernet-based network for connections between in-vehicle electronicsystems, and typically defines a physical network that is used toconnect components within a car using a wired network. Ethernet is afamily of computer networking technologies commonly used in Local AreaNetworks (LAN), Metropolitan Area Networks (MAN) and Wide Area Networks(WAN). It was commercially introduced in 1980 and first standardized in1983 as IEEE 802.3, and has since been refined to support higher bitrates and longer link distances. The Ethernet standards comprise severalwiring and signaling variants of the OSI physical layer in use withEthernet. Systems communicating over Ethernet divide a stream of datainto shorter pieces called frames. Each frame contains source anddestination addresses, and error-checking data so that damaged framescan be detected and discarded; most often, higher-layer protocolstrigger retransmission of lost frames. As per the OSI model, Ethernetprovides services up to and including the data link layer. Since itscommercial release, Ethernet has retained a good degree of backwardcompatibility. Features such as the 48-bit MAC address and Ethernetframe format have influenced other networking protocols. Simple switchedEthernet networks, while a great improvement over repeater-basedEthernet, suffer from single points of failure, attacks that trickswitches or hosts into sending data to a machine even if it is notintended for it, scalability and security issues with regard toswitching loops, broadcast radiation and multicast traffic, andbandwidth choke points where a lot of traffic is forced down a singlelink.

Advanced networking features in switches use shortest path bridging(SPB) or the spanning-tree protocol (STP) to maintain a loop-free,meshed network, allowing physical loops for redundancy (STP) orload-balancing (SPB). Advanced networking features also ensure portsecurity, provide protection features such as MAC lockdown and broadcastradiation filtering, use virtual LANs to keep different classes of usersseparate while using the same physical infrastructure, employ multilayerswitching to route between different classes, and use link aggregationto add bandwidth to overloaded links and to provide some redundancy.IEEE 802.1aq (shortest path bridging) includes the use of the link-staterouting protocol IS-IS to allow larger networks with shortest pathroutes between devices.

A data packet on an Ethernet link is called an Ethernet packet, whichtransports an Ethernet frame as its payload. An Ethernet frame ispreceded by a preamble and Start Frame Delimiter (SFD), which are bothpart of the Ethernet packet at the physical layer. Each Ethernet framestarts with an Ethernet header, which contains destination and sourceMAC addresses as its first two fields. The middle section of the frameis payload data including any headers for other protocols (for example,Internet Protocol) carried in the frame. The frame ends with a framecheck sequence (FCS), which is a 32-bit cyclic redundancy check used todetect any in-transit corruption of data. Automotive Ethernet isdescribed in a book by Charles M. Kozierok, Colt Correa, Robert B.Boatright, and Jeffrey Quesnelle entitled: “Automotive Ethernet: TheDefinitive Guide”, published 2014 by Interpid Control Systems [ISBN-13:978-0-9905388-0-6], and in a white paper document No. 915-3510-01 Rev. Apublished May 2014 by Ixia entitled: “Automotive Ethernet: An Overview”,which are both incorporated in their entirety for all purposes as iffully set forth herein.

100BaseT1. 100BASE-T1 (and upcoming 1000Base-T1) is an Ethernetautomotive standard, standardized in IEEE 802.3bw-2015 Clause 96 andentitled: “802.3bw-2015 —IEEE Standard for Ethernet Amendment 1:Physical Layer Specifications and Management Parameters for 100 Mb/sOperation over a Single Balanced Twisted Pair Cable (100BASE-T1)”. Thedata is transmitted over a single copper pair, 3 bits per symbol (PAM3),and it supports only full-duplex, transmitting in both directionssimultaneously. The twisted-pair cable is required to support 66 MHz,with a maximum length of 15 m. The standard is intended for automotiveapplications or when Fast Ethernet is to be integrated into anotherapplication.

BroadR-Reach®. BroadR-Reach® technology is an Ethernet physical layerstandard designed for use in automotive connectivity applications.BroadR-Reach® technology allows multiple in-vehicle systems tosimultaneously access information over unshielded single twisted paircable, intended for reduced connectivity costs and cabling weight. UsingBroadR-Reach® technology in automotive enables the migration frommultiple closed applications to a single open, scalable Ethernet-basednetwork within the automobile. This allows automotive manufacturers toincorporate multiple electronic systems and devices, such as advancedsafety features (i.e. 360-degree surround view parking assistance,rear-view cameras and collision avoidance systems) and comfort andinfotainment features. The automotive-qualified BroadR-Reach® Ethernetphysical layer standard can be combined with IEEE 802.3 compliant switchtechnology to deliver 100 Mbit/s over unshielded single twisted paircable.

The BroadR-Reach automotive Ethernet standard realizes simultaneoustransmit and receive (i.e., full-duplex) operations on a single-paircable instead of the half-duplex operation in 100BASE-TX, which uses onepair for transmit and one for receive to achieve the same data rate. Inorder to better de-correlate the signal, the digital signal processor(DSP) uses a highly optimized scrambler when compared to the scramblerused in 100BASE-TX. This provides a robust and efficient signalingscheme required by automotive applications. The BroadR-Reach automotiveEthernet standard uses a signaling scheme with higher spectralefficiency than that of 100BASE-TX. This limits the signal bandwidth ofAutomotive Ethernet to 33.3 MHz, which is about half the bandwidth of100BASE-TX. A lower signal bandwidth improves return loss, reducescrosstalk, and ensures that BroadR-Reach® automotive Ethernet standardpasses the stringent automotive electromagnetic emission requirements.The physical layer of BroadR-Reach® is described in a specificationauthored by Dr. Bernd Korber and published Nov. 28, 2014 by the OPENAlliance, entitled: “BroadR-Reach® Definitions for CommunicationChannel—Version 2.0”, which is incorporated in its entirety for allpurposes as if fully set forth herein.

IEEE 802.3bv™. Changes to IEEE Std 802.3-2015 that adds Clause 115 andAnnex 115A are described in IEEE Std 802.3bv-2017 entitled: “Amendment9: Physical Layer Specifications and Management Parameters for 1000 Mb/sOperation Over Plastic Optical Fiber” approved 14 Feb. 2017 [ISBN978-5044-3721-9], which is incorporated in its entirety for all purposesas if fully set forth herein. This amendment adds point-to-point 1000Mb/s Physical Layer (PHY) specifications and management parameters foroperation on duplex plastic optical fiber (POF) targeting use inautomotive, industrial, home-network, and other applications.

IEEE 802.3bp™. Changes to IEEE Std 802.3-2015 that adds Clause 97 andClause 98 are described in IEEE Std 802.3 bp-2016 entitled: “Amendment4: Physical Layer Specifications and Management Parameters for 1 Gb/sOperation over a Single Twisted-Pair Copper Cable” approved 30 Jun. 2016[ISBN 978-1-5044-2288-8], which is incorporated in its entirety for allpurposes as if fully set forth herein. This amendment addspoint-to-point 1 Gb/s Physical Layer (PHY) specifications and managementparameters for operation on a single balanced twisted-pair copper cablein automotive and other applications not utilizing the structured wiringplant.

A method and a device for recording data or for transmitting stimulationdata, which are transmitted in Ethernet-based networks of vehicles, aredescribed in U.S. Patent Application No. 2015/0071115 to Neff et al.entitled: “Data Logging or Stimulation in Automotive Ethernet NetworksUsing the Vehicle Infrastructure”, which is incorporated in its entiretyfor all purposes as if fully set forth herein. A method for recordingdata is described, wherein the data are transmitted from a transmittingcontrol unit to a receiving control unit of a vehicle via acommunication system of the vehicle. The communication system comprisesan Ethernet network, wherein the data are conducted from a transmissioncomponent to a reception component of the Ethernet network via atransmission path, and wherein the data are to be recorded at a loggingcomponent of the Ethernet network, which does not lie on thetransmission path. The method comprises the configuration of anintermediate component of the Ethernet network, which lies on thetransmission path, to transmit a copy of the data as logging data to thelogging component; and the recording of the logging data at the loggingcomponent.

A backbone network system for a vehicle enables high-speed andlarge-capacity data transmission between integrated control modulesmounted in the vehicle, such that communication can be maintainedthrough another alternative communication line when an error occurs in aspecific communication line, is described in U.S. Pat. No. 9,172,635 toKim et al. entitled: “Ethernet backbone network system for vehicle andmethod for controlling fail safe of the ethernet backbone networksystem”, which is incorporated in its entirety for all purposes as iffully set forth herein. The backbone network system enables variouskinds of integrated control modules mounted in the vehicle to performlarge-capacity and high-speed communications, based on Ethernetcommunication, by connecting domain gateways of the integrated controlmodules through an Ethernet backbone network, and provides a fastfail-safe function so that domain gateways can perform communicationsthrough another communication line when an error occurs in acommunication line between the domain gateways.

A system and method for managing a vehicle Ethernet communicationnetwork are disclosed in U.S. Pat. No. 9,450,911 to CHA et al. entitled:“System and method for managing ethernet communication network for usein vehicle”, which is incorporated in its entirety for all purposes asif fully set forth herein. More specifically, each unit in a vehicleEthernet communication network is configured to initially enter apower-on (PowerOn) mode when is applied to each unit of the vehicle toinitialize operational programs. Once powered on, each unit enters anormal mode in which a node for each unit participates in a network torequest the network. Subsequently, each unit enters a sleep indication(SleepInd) mode where other nodes are not requested even though thenetwork has already been requested by the other nodes. A communicationmode is then terminated at each unit and each unit enters a wait bussleep (WaitBusSleep) mode in which all nodes connected to the networkare no longer in communication and are waiting to switch to sleep mode.Finally, each unit is powered off to prevent communication between unitsin the network.

A system that includes an on-board unit (OBU) in communication with aninternal subsystem in a vehicle on at least one Ethernet network and anode on a wireless network, is disclosed in U.S. Patent ApplicationPublication No. 2014/0215491 to Addepalli et al. entitled: “System andmethod for internal networking, data optimization and dynamic frequencyselection in a vehicular environment”, which is incorporated in itsentirety for all purposes as if fully set forth herein. A method in oneembodiment includes receiving a message on the Ethernet network in thevehicle, encapsulating the message to facilitate translation to Ethernetprotocol if the message is not in Ethernet protocol, and transmittingthe message in Ethernet protocol to its destination. Certain embodimentsinclude optimizing data transmission over the wireless network usingredundancy caches, dictionaries, object contexts databases, speechtemplates and protocol header templates, and cross layer optimization ofdata flow from a receiver to a sender over a TCP connection. Certainembodiments also include dynamically identifying and selecting anoperating frequency with least interference for data transmission overthe wireless network.

In example of a vehicle bus, such as a CAN bus, is shown in anarrangement 50 in FIG. 5. The network is typically in a vehicle, wherethe wired communication medium 16 b comprises two conductors or wires 54a and 54 b, cooperatively connected in a multi-point (‘bus’) topology.ECUs ‘A’ 56 a, ‘B’ 56 b, and ‘C’ 56 c are connected at different pointsalong the medium (or at the medium ends), and are respectively connectedto the medium 16 b by connectors 55 a, 55 b, and 55 c. The ECUs ‘A’ 56a, ‘B’ 56 b, and ‘C’ 56 c respectively comprises balanced line drivers51 a, 51 b, and 51 c, and balanced line receivers 52 a, 52 b, and 52 c,that may be part of respective CAN bus transceivers 53 a, 53 b, and 53c, that are respectively connected to the connectors 55 a, 55 b, and 55c for coupling to the medium 16 b. CAN Controllers 57 a, 57 b, and 57 care respectively coupled to the CAN transceivers 53 a, 53 b, and 53 c,for handling the lower layers of the CAN protocol. Impedances such asresistors 19 a and 19 b are connected at both ends of the medium 16 b asterminations for matching to the medium impedance for reducing signalreflections.

A vehicle bus may consist of, or may comprise, an avionics bus, used asa data bus in military, commercial and advanced models of civilianaircraft. Common avionics data bus protocols, with their primaryapplication, include Aircraft Data Network (ADN) that is an Ethernetderivative for Commercial Aircraft, Avionics Full-Duplex SwitchedEthernet (AFDX) that is a specific implementation of ARINC 664 (ADN) forCommercial Aircraft, ARINC 429: “Generic Medium-Speed Data Sharing forPrivate and Commercial Aircraft”, ARINC 664, ARINC 629 used inCommercial Aircraft (such as Boeing 777), ARINC 708: “Weather Radar forCommercial Aircraft”, ARINC 717: “Flight Data Recorder for CommercialAircraft”, ARINC 825 that is a CAN bus for commercial aircraft (forexample Boeing 787 and Airbus A350), IEEE 1394b used in some MilitaryAircraft, MIL-STD-1553 and MIL-STD-1760 for Military Aircraft, andTime-Triggered Protocol (TTP): Boeing 787 Dreamliner, Airbus A380,Fly-By-Wire Actuation Platforms from Parker Aerospace.

MIL-STD-1553. MIL-STD-1553 is a military standard published by theUnited States Department of Defense that defines the mechanical,electrical, and functional characteristics of a serial data bus. It wasoriginally designed as an avionic data bus for use with militaryavionics, but has also become commonly used in spacecraft on-board datahandling (OBDH) subsystems, both military and civil. It featuresmultiple (commonly dual) redundant balanced line physical layers, a(differential) network interface, time division multiplexing,half-duplex command/response protocol, and can handle up to 30 RemoteTerminals (devices). The MIL-STD-1553 is standardized as a Militarystandard MIL-STD-1553B dated 21 Sep. 1978 by the Department of Defenseof U.S.A. entitled: “Aircraft Internal Time Division Command/ResponseMultiplex Data Bus”, and is described in AIM Gmbh tutorial v2.3 datedNovember 2010 entitled: “MIL-STD-1553 Tutorial”, which are bothincorporated in their entirety for all purposes as if fully set forthherein.

A single bus consists of a wire pair with 70-85Ω impedance at 1 MHz.Where a circular connector is used, its center pin is used for the high(positive) Manchester bi-phase signal. Transmitters and receivers coupleto the bus via isolation transformers, and stub connections branch offusing a pair of isolation resistors and, optionally, a couplingtransformer, for reducing the impact of a short circuit and assures thatthe bus does not conduct current through the aircraft. A Manchester codeis used to present both clock and data on the same wire pair and toeliminate any DC component in the signal (which cannot pass thetransformers). The bit rate is 1.0 megabit per second (1 bit per μs).The combined accuracy and long-term stability of the bit rate is onlyspecified to be within ±0.1%; the short-term clock stability must bewithin ±0.01%. The peak-to-peak output voltage of a transmitter is 18-27V. The bus can be made dual or triply redundant by using severalindependent wire pairs, and then all devices are connected to all buses.There is provision to designate a new bus control computer in the eventof a failure by the current master controller. Usually, the auxiliaryflight control computer(s) monitor the master computer and aircraftsensors via the main data bus. A different version of the bus usesoptical fiber, which weighs less and has better resistance toelectromagnetic interference, including EMP.

A MIL-STD-1553 multiplex data bus system consists of a Bus Controller(BC) controlling multiple Remote Terminals (RT) all connected togetherby a data bus providing a single data path between the Bus Controllerand all the associated Remote Terminals. There may also be one or moreBus Monitors (BM); however, Bus Monitors are specifically not allowed totake part in data transfers, and are only used to capture or record datafor analysis, etc. In redundant bus implementations, several data busesare used to provide more than one data path, i.e. dual redundant databus, tri-redundant data bus, etc. All transmissions onto the data busare accessible to the BC and all connected RTs. Messages consist of oneor more 16-bit words (command, data, or status). The 16 bits comprisingeach word are transmitted using Manchester code, where each bit istransmitted as a 0.5 μs high and 0.5 μs low for a logical 1 or alow-high sequence for a logical 0. Each word is preceded by a 3 μs syncpulse (1.5 μs low plus 1.5 μs high for data words and the opposite forcommand and status words, which cannot occur in the Manchester code) andfollowed by an odd parity bit. Practically each word could be consideredas a 20-bit word: 3 bit for sync, 16 bit for payload and 1 bit for oddparity control. The words within a message are transmitted contiguouslyand there has to be a minimum of a 4 μs gap between messages. However,this inter-message gap can be, and often is, much larger than 4 μs, evenup to 1 ms with some older Bus Controllers. Devices have to starttransmitting their response to a valid command within 4-12 μs and areconsidered to not have received a command or message if no response hasstarted within 14 μs.

ARINC 429. ARINC 429, also known as “Mark33 Digital Information TransferSystem (DITS)” and as Aeronautical Radio INC. (ARINC), is the technicalstandard for the predominant avionics data bus used on most higher-endcommercial and transport aircraft. It defines the physical andelectrical interfaces of a two-wire data bus and a data protocol tosupport an aircraft's avionics local area network. ARINC 429 is a datatransfer standard for aircraft avionics, and uses a self-clocking,self-synchronizing data bus protocol (Tx and Rx are on separate ports).The physical connection wires are twisted pairs carrying balanceddifferential signaling. Data words are 32 bits in length and mostmessages consist of a single data word. Messages are transmitted ateither 12.5 or 100 kbit/s to other system elements that are monitoringthe bus messages. The transmitter constantly transmits either 32-bitdata words or the NULL state. A single wire pair is limited to onetransmitter and no more than 20 receivers. The protocol allows forself-clocking at the receiver end, thus eliminating the need to transmitclocking data. The ARINC 429 unit of transmission is a fixed-length32-bit frame, which the standard refers to as a ‘word’. The bits withinan ARINC 429 word are serially identified from Bit Number 1 to BitNumber 32 or simply Bit 1 to Bit 32. The fields and data structures ofthe ARINC 429 word are defined in terms of this numbering. The ARINC 429is described in Avionics Interface Technologies Doc. No. 40100001(downloaded from the Internet on November 2016) entitled: “ARINC 429Protocol Tutorial”, and in an ARINC Specification 429 prepared byAirlines Electronic Engineering Committee and published May 17, 2004 byAeronautical Radio, Inc. entitled: “Mark 33 Digital Information TransferSystem (DITS)—Part 1—Functional Description, Electrical Interface, LabelAssignments and Word Formats”, which are both incorporated in theirentirety for all purposes as if fully set forth herein. ARINC 429interface may use ‘ARINC 429 Bus Interface—DirectCore’ v5.0 availablefrom Actel Corporation (headquartered in Mountain-View, Calif., USA)described in Document No. 51700055-5/9.06 published September 2006,which is incorporated in its entirety for all purposes as if fully setforth herein.

Memory. The terms “memory” and “storage” are used interchangeably hereinand refer to any physical component that can retain or store information(that can be later retrieved) such as digital data on a temporary orpermanent basis, typically for use in a computer or other digitalelectronic device. A memory can store computer programs or any othersequence of instructions, or data such as files, text, numbers, audioand video, as well as any other form of information represented as astring of bits or bytes. The physical means of storing information maybe electrostatic, ferroelectric, magnetic, acoustic, optical, chemical,electronic, electrical, or mechanical. A memory may be in a form ofIntegrated Circuit (IC, a.k.a. chip or microchip). Alternatively or inaddition, the memory may be in the form of a packaged functionalassembly of electronic components (module). Such module may be based ona PCB (Printed Circuit Board) such as PC Card according to PersonalComputer Memory Card International Association (PCMCIA) PCMCIA 2.0standard, or a Single In-line Memory Module (SIMM) (or DIMM) which isstandardized under the JEDEC JESD-21C standard. Further, a memory may bein the form of a separately rigidly enclosed box such as a hard-diskdrive.

Semiconductor memory may be based on Silicon-On-Insulator (SOI)technology, where a layered silicon-insulator-silicon substrate is usedin place of conventional silicon substrates in semiconductormanufacturing, especially microelectronics, to reduce parasitic devicecapacitance and thereby improving performance. SOI-based devices differfrom conventional silicon-built devices in that the silicon junction isabove an electrical insulator, typically silicon dioxide or sapphire(these types of devices are called silicon on sapphire, or SOS, and areless common). SOI-Based memories include Twin Transistor RAM (TTRAM) andZero-capacitor RAM (Z-RAM).

A memory may be a volatile memory, where a continuous power is requiredto maintain the stored information such as RAM (Random Access Memory),including DRAM (Dynamic RAM) or SRAM (Static RAM), or alternatively be anon-volatile memory which does not require a maintained power supply,such as Flash memory, EPROM, EEPROM and ROM (Read-Only Memory). Volatilememories are commonly used where long-term storage is required, whilenon-volatile memories are more suitable where fast memory access isrequired. Volatile memory may be dynamic, where the stored informationis required to be periodically refreshed (such as re-read and thenre-written) such as DRAM, or alternatively may be static, where there isno need to refresh as long as power is applied, such as RAM. In somecases, a small battery is connected to a low-power consuming volatilememory, allowing its use as a non-volatile memory.

A memory may be read/write (or mutable storage) memory where data may beoverwritten more than once and typically at any time, such as RAM andHard Disk Drive (HDD). Alternatively, a memory may be an immutablestorage where the information is retained after being written once. Oncewritten, the information can only be read and typically cannot bemodified, sometimes referred to as Write Once Read Many (WORM). The datamay be written at the time of manufacture of the memory, such asmask-programmable ROM (Read Only Memory) where the data is written intothe memory a part of the IC fabrication, CD-ROM (CD—Compact Disc) andDVD-ROM (DVD—Digital Versatile Disk, or Digital Video Disk).Alternately, the data may be once written to the “write once storage” atsome point after manufacturing, such as Programmable Read-Only Memory(PROM) or CD-R (Compact Disc-Recordable).

A memory may be accessed using “random access” scheme, where anylocation in the storage can be accessed at any moment in typically thesame time, such as RAM, ROM or most semiconductor-based memories.Alternatively, a memory may be of “sequential access” type, where thepieces of information are gathered or stored in a serial order, andtherefore the time to access a particular piece of information or aparticular address depends upon which piece of information was lastaccessed, such as magnetic tape-based storage. Common memory devices arelocation-addressable, where each individually accessible unit of data instorage is selected using its numerical memory address. Alternatively, amemory may be file-addressable, where the information is divided intofiles of variable length, and a file is selected by using a directory orfile name (typically a human readable name), or may becontent-addressable, where each accessible unit of information isselected based on the stored content (or part of). File addressabilityand content addressability commonly involves additional software(firmware), hardware, or both.

Various storage technologies are used for the medium (or media) thatactually holds the data in the memory. Commonly in use aresemiconductor, magnetic, and optical mediums. Semiconductor based mediumis based on transistors, capacitors or other electronic components in anIC, such as RAM, ROM and Solid-State Drives (SSDs). A currently popularnon-volatile semiconductor technology is based on a flash memory, andcan be electrically erased and reprogrammed. The flash memory is basedon NOR- or NAND-based single-level cells (SLC) or multi-level cells(MLC), made from floating-gate transistors. Non-limiting examples ofapplications of flash memory include personal and laptop computers,PDAs, digital audio players (MP3 players), digital cameras, mobilephones, synthesizers, video games consoles, scientific instrumentation,industrial robotics and medical electronics. The magnetic storage usesdifferent types of magnetization on a magnetic or a ferromagnetic coatedsurface as a medium for storing the information. The information isaccessed by read/write heads or other transducers. Non-limiting examplesof magnetic-based memory are Floppy disk, magnetic tape data storage andHDD.

In optical storage, typically an optical disc is used that storesinformation in deformities on the surface of a circular disc, and theinformation is read by illuminating the surface with a laser diode andobserving the reflection. The deformities may be permanent (read onlymedia), formed once (write once media) or reversible (recordable orread/write media). Non-limiting examples of read-only storage, commonlyused for mass distribution of digital information such as music, audio,video or computer programs, include CD-ROM, BD-ROM (BD—Blu-ray Disc) andDVD-ROM. Non-limiting examples of write-once storage are CD-R, DVD-R,DVD+R, and BD-R, and non-limiting examples of recordable storage areCD-RW (Compact Disc-ReWritable), DVD-RW, DVD+RW, DVD-RAM, and BD-RE(Blu-ray Disc Recordable Erasable). Another non-limiting example ismagneto-optical disc storage, where the magnetic state of aferromagnetic surface stores the information, which can be readoptically. 3D optical data storage is an optical data storage, in whichinformation can be recorded and/or read, with three-dimensionalresolution.

A storage medium may be removable, designed to be easily removed from,and easily installed or inserted into the computer by a person,typically without the need for any tool, and without needing to poweroff the computer or the associated drive. Such a capability allows forarchiving, transporting data between computers, and buying and sellingsoftware. The medium may be read using a reader or player that reads thedata from the medium, may be written by a burner or writer, or may beused for writing and reading by a writer/reader commonly referred to asa drive. Commonly in the case of magnetic or optical based mediums, themedium has the form factor of a disk, which is typically a round plateon which the data is encoded, respectively known as magnetic disc andoptical disk. The machine that is associated with reading data from andwriting data onto a disk is known as a disk drive. Disk drives may beinternal (integrated within the computer enclosure) or may be external(housed in a separate box that connects to the computer). Floppy disks,that can be read from or written on by a floppy drive, are anon-limiting example of removable magnetic storage medium, and CD-RW(Compact Disc-ReWritable) is a non-limiting example of a removableoptical disk. A commonly-used non-volatile removable semiconductor basedstorage medium is referred to as a memory card. A memory card is a smallstorage device, commonly based on flash memory, and can be read by asuitable card reader.

A memory may be accessed via a parallel connection or bus (wherein eachdata word is carried in parallel on multiple electrical conductors orwires), such as PATA, PCMCIA or EISA, or via serial bus (such asbit-serial connections) such as USB or Ethernet based on IEEE802.3standard, or a combination of both. The connection may further be wiredin various topologies such as multi-drop (electrical parallel),point-to-point, or daisy-chain. A memory may be powered via a dedicatedport or connector, or may be powered via a power signal carried over thebus, such as SATA or USB.

A memory may be provided according to a standard, defining its formfactor (such as its physical size and shape) and electrical connections(such as power and data interface). A standard-based memory may beeasily inserted to, or removed from, a suitable corresponding slot(a.k.a. expansion slots) of a computer or other digital device. In onenon-limiting example, a memory card using a PC Card form factoraccording to PCMCIA 2.0 (or JEIDA 4.1) is used that is suitable formounting into a corresponding PCMCIA-compatible slot, supporting 16 or32-bit width interface, and connected via 68 pin connectors. Similarly,CardBus according to PCMCIA 5.0 may be used. In one non-limitingexample, the memory is in the form of SD (Secure Digital) Card, based onstandard by SD Card Association (SDA), which is commonly used in manysmall portable devices such as digital video camcorders, digitalcameras, audio players and mobile phones. Other types of memory cardsmay be equally used, such as CompactFlash (CF), MiniSD card, MicroSDCard, and xD-Picture Card.

In another non-limiting example, a memory may be provided as a USB drive(such as a USB Flash drive), which is a portable enclosed card thatplugs into a computer USB port and communicates with a USB host. Suchflash-based memory drives are commonly referred to as “thumb drives”,“jump drives”, and “memory sticks”. Such USB mass storage devices andothers are described in “Chapter 1: Mass Storage basics”, downloadedOctober 2011 from:http://www.lvr.com/files/usb_mass_storage_chapter_1.pdf, which isincorporated in its entirety for all purposes as if fully set forthherein. In another non-limiting example, the memory is designed to fitinto a drive bay in a computer enclosure. Commonly such drive bays arestandard-sized, and used to store disk drives. The drives may be usuallysecured with screws or using a tool-less fasteners. A current popularstandard is the 3.5 inches (3.5″) bays, which dimensions are specifiedin SFF standard specifications SFF-8300 and SFF-8301, which wereincorporated into the EIA (Electronic Industries Association) standardEIA-470.

Traditionally, computer-related storage was categorized to main memory,secondary and tertiary storages, having different latency (access time),capacity, and size. The main memory (or primary memory or internalmemory) referred to the memory that was directly accessible by the CPU,and typically stored the program to be executed by the processor. Thesecondary storage (or external memory or auxiliary storage) referred toa memory which was not directly accessible to the CPU and thus requiredinput/output channels, commonly offering larger storage capacity thanthe main memory. The tertiary storage involved mass storage media,commonly associated with a dismount removable media, used for archivingrarely accessed information. The latency of accessing a particularlocation is typically nanoseconds for primary storage, milliseconds forsecondary storage, and seconds for tertiary storage. The capacity of amemory is commonly featured in bytes (B), where the prefix ‘K’ is usedto denote kilo=2¹⁰=1024¹=1024, the prefix ‘M’ is used to denotemega=2²⁰=1024²=1,048,576, the prefix ‘G’ is used to denotegiga=2³⁰=1024³=1,073,741,824, and the prefix ‘T’ is used to denotetera=2⁴⁰=1024⁴=1,099,511,627,776.

A memory may be Direct-Attached Storage (DAS), where the memory isdirectly connected to a host, computer, server, or workstation, commonlywithout a network in between. Common examples involve a number of HardDisk Drives (HDDs) connected to a processor or a computer through a HostBus Adapter (HBA). Commonly, serial and point-to-point connections areused, such as SATA, eSATA, SCSI, SAS and Fibre Channel. Alternatively, amemory can be part of a Network-Attached Storage (NAS), and aself-contained file level storage (typically arranged as a server) maybe connected to a network, providing data sharing to other devices (suchas heterogeneous clients), commonly via a network device such as a hub,switch or router. NAS is specialized for its task by its hardware,software, or both, and thus provides faster data access, easieradministration, and simple configuration. NAS is typically associatedwith an LAN, and provides an Ethernet interface based on IEEE802.3standard may be used such as 10/100BaseT, 1000BaseT/TX (gigabitEthernet), 10 gigabit Ethernet (10GE or 10 GbE or 10 GigE per IEEEStandard 802.3ae-2002as standard), 40 Gigabit Ethernet (40 GbE), or 100Gigabit Ethernet (100 GbE as per Ethernet standard IEEE P802.3ba). Inanother alternative, a memory may be part of a Storage Area Network(SAN), which is a high-speed (commonly dedicated) network (orsub-network) for sharing storage devices, such as disk arrays, tapelibraries and optical jukeboxes. The SAN allows multiple computers orservers to access multiple storage devices using a network such as WANor LAN. SAN often utilizes a Fibre Channel fabric topology, made up of anumber of Fibre Channel switches.

Blu-ray Disc (official abbreviation BD) is an optical disc storagemedium designed to supersede the DVD format, where blue laser is used toread the disc, allowing information to be stored at a greater densitythan is possible with the longer-wavelength red laser used for DVDs. Thedisc diameter is 120 mm and the disc thickness is 1.2 mm of plasticoptical disc, the same size as DVDs and CDs. Blu-ray Discs contain 25 GB(23.31 GiB) per layer, with dual layer discs (50 GB) being the norm forfeature-length video discs. Triple layer discs (100 GB) and quadruplelayers (128 GB) are available for BD-XL Blu-ray re-writer drives. TheBlu-ray technology and its uses are described in the White Paper“Blu-ray Disc Format, 4. Key Technologies”, by Blu-ray Disc Founders,August 2004, in the brochure entitled: “Blu-ray Technology—DISCover theinfinite storage media”, by DISC Archiving Systems B.V., 2010, and in aWhitepaper entitled: “Sustainable Archival Storage—The Benefits ofOptical Archiving”, by DISC Archiving Systems B.V., downloaded fromwww.disc-group.com, which are all incorporated in their entirety for allpurposes as if fully set forth herein.

Today, Hard Disk Drives (HDD) are used as secondary storage in generalpurpose computers, such as desktop personal computers and laptops. AnHDD is a non-volatile, random access digital data storage device,featuring rotating rigid platters on a motor-driven spindle within aprotective enclosure. The enclosure may be internal to the computersystem enclosure, or external. Data is magnetically read from, andwritten to, the platter by read/write heads that float on a film or airabove the platters. The HDDs are typically interfaced using high-speedinterfaces, commonly of a serial type. Common HDDs structure,characteristics, operation, form factors, and interfacing are describedin “Hard-Disk Basics” compiled from PCGUIDE.COM by Mehedi Hasan, whichis incorporated in its entirety for all purposes as if fully set forthherein. Most SSDs include a controller that incorporates the electronicsthat bridge the NAND memory components to the host computer. Thecontroller is an embedded processor that executes firmware-level codeand is one of the most important factors of SSD performance. Functionsperformed by the controller include Error correction (ECC), Wearleveling, Bad block mapping, Read scrubbing and read disturb management,Read and write caching, and Garbage collection. Information about SSDtechnology, marketing and applications are provided in Martin B., Dellentitled: “DELL Solid State Disk (SSD) Drive—Storage Solutions forSelect Poweredge Server”, May 2009, in Janukowicz J., Reisel D.,White-Paper entitled: “MLC Solid State Drives: Accelerating the Adoptionof SSDs”, IDC #213730, September 2008, and in Dufrasne B., Blum K,Dubberke U., IBM Corp. Redbooks Redpaper entitled: “DS8000: IntroducingSolid State Drives” (2009), which are all incorporated in their entiretyfor all purposes as if fully set forth herein.

PLD. A Programmable Logic Device (PLD) is an electronic component usedto build reconfigurable circuits. A PLD may be reconfigured byprogramming in the field by a user to provide a logic function. Examplesof PLDs include PAL (Programmable Array Logic), GAL (Generic ArrayLogic), CPLD (Complex Programmable Logic Device), and FPGA(Field-Programmable Gate Array). A PLD is effectively a combination of alogic device and a memory device, where the memory is used to store thepattern that was given to the chip during programming. The memory istypically electrically programmable and erasable, may be volatile ornon-volatile, and is commonly an integrated circuit using common storagetechnology such as Silicon antifuses, SRAM, EPROM or EEPROM cells, orFlash memory. Further, the memory may be internal to the PLD or externalto it. The programming typically uses a programming language such asVerilog and VHDL.

A CPLD is a PLD with complexity between that of PALs and FPGAs, andarchitectural features of both. The building block of a CPLD is themacrocell, which contains logic implementing disjunctive normal formexpressions and more specialized logic operations, thus forming thelogic functions with sea-of-gates (for example, a sum of products).Typically, a CPLD contain on-chip non-volatile memory. An FPGA is a PLDthat contains programmable logic components called “logic blocks”, and ahierarchy of reconfigurable interconnects that allow the blocks to bewired together. Logic blocks can be configured to perform complexcombinational functions, or merely simple logic gates like AND and XOR.In most FPGAs, the logic blocks also include memory elements, which maybe simple flip-flops or complete blocks of memory. In many cases, anFPGA uses a memory external to the component.

PLDs such as CPLD and FPGA are field programmable, allowing a user tochange the logic per specific needs, and further for updating theprogramming by storing a new content into the PLD associated memory,being internal or external to the device. A processor (or a directmemory) is connected to the PLD associated memory, and writes theprogramming content into it. In case of malware in the system or anerror in the communication link, the written content may be damaged,similar to the above discussion regarding writing to a peripheral devicesuch as an HDD.

Message Authentication. Authentication refers to the act of confirmingthe truth of an attribute of a single piece of data claimed true by anentity. In contrast with identification, which refers to the act ofstating or otherwise indicating a claim purportedly attesting to aperson or thing's identity, authentication is the process of actuallyconfirming that identity. Authentication typically involves verifyingthe validity of at least one form of identification. Messageauthentication or data origin authentication is a property that amessage has not been modified while in transit (data integrity) and thatthe receiving party can verify the source of the message.

Message authentication is typically achieved by using MessageAuthentication Codes (MACs), Authenticated Encryption (AE), or digitalsignatures. The Message Authentication Code, also known as digitalauthenticator, is used as an integrity check based on a secret keyshared by two parties to authenticate information transmitted betweenthem. It is typically based on using a cryptographic hash or symmetricencryption algorithm, and the authentication key is only shared by atleast two parties or two communicating devices but it will fail in theexistence of a third party since the algorithm will no longer beeffective in detecting forgeries. In addition, the key must also berandomly generated to avoid its recovery through brute force searchesand related key attacks designed to identify it from the messagestransiting the medium.

Message Authentication Code (MAC). A message authentication code (MAC),sometimes known as a tag, refers to a cryptographic checksum thatresults from passing data through a message authentication algorithm.Typically a MAC is a short piece of information used to authenticate amessage, to confirm that the message came from the stated sender (itsauthenticity) and has not been changed. The MAC value protects both amessage's data integrity as well as its authenticity, by allowingverifiers (who also possess the secret key) to detect any changes to themessage content. Commonly, a message authentication code consists ofthree algorithms: A key generation algorithm selects a key from the keyspace uniformly at random; a signing algorithm efficiently returns a taggiven the key and the message; and a verifying algorithm efficientlyverifies the authenticity of the message given the key and the tag. Thatis, return accepted when the message and tag are not tampered with orforged, and otherwise return rejected.

A MAC function typically resists existential forgery underchosen-plaintext attacks. This means that even if an attacker has accessto an oracle which possesses the secret key and generates MACs formessages of the attacker's choosing, the attacker cannot guess the MACfor other messages (which were not used to query the oracle) withoutperforming infeasible amounts of computation. MACs differ from digitalsignatures as MAC values are both generated and verified using the samesecret key. This implies that the sender and receiver of a message mustagree on the same key before initiating communications, as is the casewith symmetric encryption. For the same reason, MACs do not provide theproperty of non-repudiation offered by signatures specifically in thecase of a network-wide shared secret key: any user who can verify a MACis also capable of generating MACs for other messages. In contrast, adigital signature is generated using the private key of a key pair,which is public-key cryptography. Since this private key is onlyaccessible to its holder, a digital signature proves that a document wassigned by none other than that holder. Thus, digital signatures do offernon-repudiation. However, non-repudiation can be provided by systemsthat securely bind key usage information to the MAC key; the same key isin the possession of two people, but one has a copy of the key that canbe used for MAC generation while the other has a copy of the key in ahardware security module that only permits MAC verification.

MAC algorithms can be constructed from other cryptographic primitives,like cryptographic hash functions (as in the case of HMAC) or from blockcipher algorithms (OMAC, CBC-MAC and PMAC). However many of the fastestMAC algorithms like UMAC and VMAC are constructed based on universalhashing. Additionally, the MAC algorithm can deliberately combine two ormore cryptographic primitives, so as to maintain protection even if oneof them is later found to be vulnerable. For instance, in TransportLayer Security (TLS), the input data is split in halves that are eachprocessed with a different hashing primitive (MD5 and SHA-1) then XORedtogether to output the MAC.

The FEDERAL INFORMATION PROCESSING STANDARDS PUBLICATION—FPS PUB 198-1Standard entitled: “The Keyed-Hash Message Authentication Code (HMAC)”published 2008 by U.S. Department of Commerce, National Institute ofStandards and Technology (NIST), which is incorporated in its entiretyfor all purposes as if fully set forth herein, describes a keyed-HashMessage Authentication Code (HMAC), a mechanism for messageauthentication using cryptographic hash functions. HMAC can be used withany iterative Approved cryptographic hash function, in combination witha shared secret key. A Keyed-hash message authentication code (HMAC)refers to a message authentication code that uses a cryptographic key inconjunction with a hash function. A Cryptographic key (key) is typicallya parameter used in conjunction with a cryptographic algorithm thatdetermines the specific operation of that algorithm. In this Standard,the cryptographic key is used by the HMAC algorithm to produce a MAC onthe data, and Hash function refers to a mathematical function that mapsa string of arbitrary length (up to a pre-determined maximum size) to afixed length string.

Message Authentication Code (MAC) algorithms are data integritymechanisms that compute a short string (the Message Authentication Codeor MAC) as a complex function of every bit of the data and of a secretkey. Their main security property is unforgeability: someone who doesnot know the secret key should not be able to predict the MAC on any newdata string. MAC algorithms can be used to provide data integrity. Theirpurpose is the detection of any unauthorized modification of the datasuch as deletion, insertion, or transportation of items within data.This includes both malicious and accidental modifications. MACalgorithms can also provide data origin authentication. This means thatthey can provide assurance that a message has been originated by anentity in possession of a specific secret key. ISO/IEC 9797-1:2011entitled: “Information technology—Security techniques—MessageAuthentication Codes (MACs)—Part 1: Mechanisms using a block cipher”specifies six MAC algorithms that use a secret key and an n-bit blockcipher to calculate an m-bit MAC, and may be applied to the securityservices of any security architecture, process, or application. ISO/IEC9797-2:2011 entitled: “Information technology—Securitytechniques—Message Authentication Codes (MACs)—Part 2: Mechanisms usinga dedicated hash-function” specifies three MAC algorithms that are basedon a dedicated hash-function and three MAC algorithms that use a secretkey and a hash-function (or its round-function) with an n-bit result tocalculate an m-bit MAC. The strength of the data integrity mechanism andmessage authentication mechanism is dependent on the length (in bits) kand secrecy of the key, on the length (in bits) n of the hash-functionand its strength, on the length (in bits) m of the MAC, and on thespecific mechanism. The first mechanism specified in ISO/IEC 9797-2:2011is commonly known as MDx-MAC. It calls the complete hash-function once,but it makes a small modification to the round-function by adding a keyto the additive constants in the round-function. The second mechanismspecified in ISO/IEC 9797-2:2011 is commonly known as HMAC. It calls thecomplete hash-function twice. The third mechanism specified in ISO/IEC9797-2:2011 is a variant of MDx-MAC that takes as input only shortstrings (at most 256 bits). It offers a higher performance forapplications that work with short input strings only.

IEEE 802.1X. Port-based Network Access Control (PNAC) allows a networkadministrator to restrict the use of IEEE 802 LAN service access points(ports) to secure communication between authenticated and authorizeddevices. An architecture, functional elements, and protocols thatsupport mutual authentication between the clients of ports attached tothe same LAN and secure communication between the ports are described inIEEE Std 802.1X™-2010 Published 5 Feb. 2010 [ISBN 978-0-7381-6145-7STD96008] by IEEE Standard for Local and metropolitan area networks andentitled: “Port-Based Network Access Control”, which is incorporated inits entirety for all purposes as if fully set forth herein.

IEEE 802.1X defines the encapsulation of the Extensible AuthenticationProtocol (EAP) over IEEE 802, which is known as “EAP over LAN”—EAPOL.The EAPOL protocol was also modified for use with IEEE 802.1AE(“MACsec”) and IEEE 802.1AR (Secure Device Identity, DevID) in IEEE802.1X-2010 to support service identification and optional point topoint encryption over the local LAN segment. IEEE 802.1X authenticationinvolves three parties: a supplicant, an authenticator, and anauthentication server. The supplicant is a client device (such as alaptop) that wishes to attach to the LAN/WLAN. The term ‘supplicant’ isalso used interchangeably to refer to the software running on the clientthat provides credentials to the authenticator. The authenticator is anetwork device, such as an Ethernet switch or wireless access point; andthe authentication server is typically a host running softwaresupporting the RADIUS and EAP protocols. In some cases, theauthentication server software may be running on the authenticatorhardware.

The authenticator acts like a security guard to a protected network. Thesupplicant (i.e., client device) is not allowed access through theauthenticator to the protected side of the network until thesupplicant's identity has been validated and authorized. With IEEE802.1X port-based authentication, the supplicant provides credentials,such as user name/password or digital certificate, to the authenticator,and the authenticator forwards the credentials to the authenticationserver for verification. If the authentication server determines thecredentials are valid, the supplicant (client device) is allowed toaccess resources located on the protected side of the network. EAPOLoperates at the network layer on top of the data link layer, and inEthernet II framing protocol has an EtherType value of 0x888E.

IEEE 802.1X-2001 defines two logical port entities for an authenticatedport—the “controlled port” and the “uncontrolled port”. The controlledport is manipulated by the 802.1X PAE (Port Access Entity) to allow (inthe authorized state) or prevent (in the unauthorized state) networktraffic ingressing and egressing to/from the controlled port. Theuncontrolled port is used by the 802.1X PAE to transmit and receiveEAPOL frames.

A typical authentication procedure consists of: (1) Initialization—Ondetection of a new supplicant, the port on the switch (authenticator) isenabled and set to the “unauthorized” state. In this state, only 802.1Xtraffic is allowed; other traffic, such as the Internet Protocol (andwith that TCP and UDP), is dropped; (2) Initiation—To initiateauthentication the authenticator will periodically transmit EAP-RequestIdentity frames to a special Layer 2 address (01:80:C2:00:00:03) on thelocal network segment. The supplicant listens on this address, and onreceipt of the EAP-Request Identity frame it responds with anEAP-Response Identity frame containing an identifier for the supplicantsuch as a User ID. The authenticator then encapsulates this Identityresponse in a RADIUS Access-Request packet and forwards it on to theauthentication server. The supplicant may also initiate or restartauthentication by sending an EAPOL-Start frame to the authenticator,which will then reply with an EAP-Request Identity frame; (3)Negotiation—(Technically EAP negotiation) The authentication serversends a reply (encapsulated in a RADIUS Access-Challenge packet) to theauthenticator, containing an EAP Request specifying the EAP Method (Thetype of EAP based authentication it wishes the supplicant to perform).The authenticator encapsulates the EAP Request in an EAPOL frame andtransmits it to the supplicant. At this point the supplicant can startusing the requested EAP Method, or do an NAK (“NegativeAcknowledgement”) and respond with the EAP Methods it is willing toperform; and (4) Authentication—If the authentication server andsupplicant agree on an EAP Method, EAP Requests and Responses are sentbetween the supplicant and the authentication server (translated by theauthenticator) until the authentication server responds with either anEAP-Success message (encapsulated in a RADIUS Access-Accept packet), oran EAP-Failure message (encapsulated in a RADIUS Access-Reject packet).If authentication is successful, the authenticator sets the port to the“authorized” state and normal traffic is allowed, if it is unsuccessfulthe port remains in the “unauthorized” state. When the supplicant logsoff, it sends an EAPOL-logoff message to the authenticator, theauthenticator then sets the port to the “unauthorized” state, once againblocking all non-EAP traffic.

IEEE 802.1AE. MAC Security standard (also known as MACsec) definesconnectionless data confidentiality and integrity for media accessindependent protocols, and is described in IEEE Std 802.1AE™-2006Published 18 Aug. 2006 [ISBN 0-7381-4991-8 SS95549] by IEEE Standard forLocal and metropolitan area networks and entitled: “Media Access Control(MAC) Security”, which is incorporated in its entirety for all purposesas if fully set forth herein. MAC Security (MACsec), as defined by thisstandard, allows authorized systems that attach to and interconnect LANsin a network to maintain confidentiality of transmitted data and to takemeasures against frames transmitted or modified by unauthorized devices.

The IEEE 802.1AE standard specifies the implementation of a MAC SecurityEntities (SecY) that can be thought of as part of the stations attachedto the same LAN, providing secure MAC service to the client. Thestandard defines MAC sec frame format, which is similar to the Ethernetframe, but includes additional fields: Security Tag, which is anextension of the EtherType, Message authentication code (ICV), andSecure Connectivity Associations that represent groups of stationsconnected via unidirectional Secure Channels. Security Associationswithin each secure channel—Each association uses its own key (SAK), andmore than one association is permitted within the channel for thepurpose of key change without traffic interruption (standard requiresdevices to support at least two). A default cipher suite of GCM-AES-128(Galois/Counter Mode of Advanced Encryption Standard cipher with 128-bitkey), and GCM-AES-256 using a 256 bit key is also defined the standard.

Security tag inside each frame in addition to EtherType includes:association number within the channel, packet number to provide uniqueinitialization vector for encryption and authentication algorithms aswell as protection against replay attack, and optional LAN-wide securechannel identifier (not required on point-to-point links).

The IEEE 802.1AE (MACsec) standard specifies a set of protocols to meetthe security requirements for protecting data traversing Ethernet LANs.MACsec allows unauthorized LAN connections to be identified and excludedfrom communication within the network. In common with IPsec and SSL,MACsec defines a security infrastructure to provide dataconfidentiality, data integrity and data origin authentication. Byassuring that a frame comes from the station that claimed to send it,MACSec can mitigate attacks on Layer 2 protocols.

IPsec. Internet Protocol Security (IPsec) is a network protocol suitethat authenticates and encrypts the packets of data sent over a network.IPsec includes protocols for establishing mutual authentication betweenagents at the beginning of the session and negotiation of cryptographickeys to use during the session. IPsec can protect data flows between apair of hosts (host-to-host), between a pair of security gateways(network-to-network), or between a security gateway and a host(network-to-host). Internet Protocol security (IPsec) uses cryptographicsecurity services to protect communications over Internet Protocol (IP)networks, and supports network-level peer authentication, data-originauthentication, data integrity, data confidentiality (encryption), andreplay protection. IPsec is described in IETF RFC 4301 entitled:“Security Architecture for the Internet Protocol” and in IETF RFC 4309entitled: “Using Advanced Encryption Standard (AES) CCM Mode with IPsecEncapsulating Security Payload (ESP)”, both published on December 2005and which are both incorporated in their entirety for all purposes as iffully set forth herein.

IPsec is an end-to-end security scheme operating in the Internet Layerof the Internet Protocol Suite, while some other Internet securitysystems in widespread use, such as Transport Layer Security (TLS) andSecure Shell (SSH), operate in the upper layers at the Transport Layer(TLS) and the Application layer (SSH), and can automatically secureapplications at the IP layer. The IPsec suite is an open standard. IPsecuses the following protocols to perform various functions:Authentication Headers (AH) provides connectionless data integrity anddata origin authentication for IP datagrams and provides protectionagainst replay attacks; Encapsulating Security Payloads (ESP) providesconfidentiality, data-origin authentication, connectionless integrity,an anti-replay service (a form of partial sequence integrity), andlimited traffic-flow confidentiality; Security Associations (SA)provides the bundle of algorithms and data that provide the parametersnecessary for AH and/or ESP operations. The Internet SecurityAssociation and Key Management Protocol (ISAKMP) provides a frameworkfor authentication and key exchange, with actual authenticated keyingmaterial provided either by manual configuration with pre-shared keys,Internet Key Exchange (IKE and IKEv2), Kerberized Internet Negotiationof Keys (KINK), or IPSECKEY DNS records.

Metadata. The term “metadata”, as used herein, refers to data thatdescribes characteristics, attributes, or parameters of other data, inparticular, files (such as program files) and objects. Such data istypically structured information that describes, explains, locates, andotherwise makes it easier to retrieve and use an information resource.Metadata typically includes structural metadata, relating to the designand specification of data structures or “data about the containers ofdata”; and descriptive metadata about individual instances ofapplication data or the data content. Metadata may include the means ofcreation of the data, the purpose of the data, time and date ofcreation, the creator or author of the data, the location on a computernetwork where the data were created, and the standards used.

For example, metadata associated with a computer word processing filemight include the title of the document, the name of the author, thecompany to whom the document belongs, the dates that the document wascreated and last modified, keywords which describe the document, andother descriptive data. While some of this information may also beincluded in the document itself (e.g., title, author, and data),metadata may be a separate collection of data that may be storedseparately from, but associated with, the actual document. One commonformat for documenting metadata is eXtensible Markup Language (XML). XMLprovides a formal syntax, which supports the creation of arbitrarydescriptions, sometimes called “tags.” An example of a metadata entrymight be <title>War and Peace</title>, where the bracketed wordsdelineate the beginning and end of the group of characters thatconstitute the title of the document that is described by the metadata.In the example of the word processing file, the metadata (sometimesreferred to as “document properties”) is entered manually by the author,the editor, or the document manager. The metadata concept is furtherdescribed in a National Information Standards Organization (NISO)Booklet entitled: “Understanding Metadata” (ISBN: 1-880124-62-9), in theIETF RFC 5013 entitled: “The Dublin Core Metadata Element Set”, and inthe IETF RFC 2731 entitled: “Encoding Dublin Core Metadata in HTML”,which are all incorporated in their entirety for all purposes as iffully set forth herein. An extraction of metadata from files or objectsis described in a U.S. Pat. No. 8,700,626 to Bedingfield, entitled:“Systems, Methods and Computer Products for Content-Derived Metadata”,and in a U.S. Patent Application Publication 2012/0278705 to Yang etal., entitled: “System and Method for Automatically Extracting Metadatafrom Unstructured Electronic Documents”, which are both incorporated intheir entirety for all purposes as if fully set forth herein.

Metadata can be stored either internally in the same file, object, orstructure as the data (this is also called internal or embeddedmetadata), or externally in a separate file or field separated from thedescribed data. A data repository typically stores the metadata detachedfrom the data, but can be designed to support embedded metadataapproaches. Metadata can be stored in either human-readable or binaryform. Storing metadata in a human-readable format such as XML can beuseful because users can understand and edit it without specializedtools, however, these formats are rarely optimized for storage capacity,communication time, and processing speed. A binary metadata formatenables efficiency in all these respects but requires special librariesto convert the binary information into a human-readable content.

Error detection. Error detection refers to the detection of errorscaused by noise or other impairments during transmission from thetransmitter to the receiver. Error detection typically enables reliabledelivery of digital data over unreliable communication channels. Manycommunication channels are subject to channel noise, and thus errors maybe introduced during transmission from the source to a receiver.Error-detection schemes typically involve adding some redundancy (i.e.,some extra data) to a message, which receivers can use to checkconsistency of the delivered message, and to recover data that has beendetermined to be corrupted. Error-detection and correction schemes canbe either systematic or non-systematic. In a systematic scheme, thetransmitter sends the original data, and attaches a fixed number ofcheck bits (or parity data), which are derived from the data bits bysome deterministic algorithm. If only error detection is required, areceiver can simply apply the same algorithm to the received data bitsand compare its output with the received check bits; if the values donot match, an error has occurred at some point during the transmission.In a system that uses a non-systematic code, the original message istransformed into an encoded message carrying the same information andthat has at least as many bits as the original message.

Error detection is commonly realized using a suitable hash function (orchecksum algorithm). A hash function adds a fixed-length tag to amessage, which enables receivers to verify the delivered message byrecomputing the tag and comparing it with the one provided. There existsa vast variety of different hash function designs. However, some are ofparticularly widespread use because of either their simplicity or theirsuitability for detecting certain kinds of errors (e.g., the cyclicredundancy check's performance in detecting burst errors).

Parity. A parity bit is a bit that is added to a group of source bits toensure that the number of set bits (i.e., bits with value 1) in theoutcome is even or odd. It is a very simple scheme that can be used todetect single or any other odd number (i.e., three, five, etc.) oferrors in the output. An even number of flipped bits will make theparity bit appear correct even though the data is erroneous. Extensionsand variations on the parity bit mechanism are horizontal redundancychecks, vertical redundancy checks, and “double,” “dual,” or “diagonal”parity (used in RAID-DP).

Checksum. A checksum of a message is a modular arithmetic sum of messagecode words of a fixed word length (e.g., byte values). The sum may benegated by means of a ones'-complement operation prior to transmissionto detect errors resulting in all-zero messages. Checksum schemesinclude parity bits, check digits, and longitudinal redundancy checks.Some checksum schemes, such as the Damm algorithm, the Luhn algorithm,and the Verhoeff algorithm, are specifically designed to detect errorscommonly introduced by humans in writing down or rememberingidentification numbers.

CRC. A Cyclic Redundancy Check (CRC) is an error-detecting code commonlyused in digital networks and storage devices to detect accidentalchanges to raw data. Blocks of data entering these systems get a shortcheck value attached, based on the remainder of a polynomial division oftheir contents. On retrieval, the calculation is repeated and, in theevent the check values do not match, corrective action can be takenagainst data corruption. CRCs can be used for error correction. Thecheck (data verification) value is a redundancy (it expands the messagewithout adding information) and the algorithm is based on cyclic codes,and because the check value has a fixed length, the function thatgenerates it is occasionally used as a hash function. CRCs are commonlybased on the theory of cyclic error-correcting codes. Specification of aCRC code requires definition of a generator polynomial, where thispolynomial becomes the divisor in a polynomial long division, whichtakes the message as the dividend and in which the quotient is discardedand the remainder becomes the result. The important caveat is that thepolynomial coefficients are calculated according to the arithmetic of afinite field, so the addition operation can always be performedbitwise-parallel (there is no carry between digits). The length of theremainder is always less than the length of the generator polynomial,which therefore determines how long the result can be.

In practice, all commonly used CRCs employ the Galois field of twoelements, GF(2). The two elements are usually called 0 and 1,comfortably matching computer architecture. A CRC is called an n-bit CRCwhen its check value is n bits long. For a given n, multiple CRCs arepossible, each with a different polynomial. Such a polynomial hashighest degree n, which means it has n+1 terms. In other words, thepolynomial has a length of n+1; its encoding requires n+1 bits. Notethat most polynomial specifications either drop the MSB or LSB, sincethey are always 1. The simplest error-detection system, the parity bit,is in fact a trivial 1-bit CRC: it uses the generator polynomial x+1(two terms), and has the name CRC-1. A CRC-enabled device calculates ashort, fixed-length binary sequence, known as the check value or CRC,for each block of data to be sent or stored and appends it to the data,forming a codeword. When a codeword is received or read, the deviceeither compares its check value with one freshly calculated from thedata block, or equivalently, performs a CRC on the whole codeword andcompares the resulting check value with an expected residue constant. Ifthe CRC values do not match, then the block contains a data error. Thedevice may take corrective action, such as rereading the block orrequesting that it be sent again. Otherwise, the data is assumed to beerror-free (though, with some small probability, it may containundetected errors; this is the fundamental nature of error-checking).

In one example, the corruption is achieved by transmitting a signal thatchanges the value of a single bit in the message. This single bit changerenders a CRC error, which may be used by the receiving devices as anindicator of an invalidated or corrupted message that needs to beignored. Alternatively or in addition, multiple bits, which may becarried sequentially or non-sequentially in the message (frame orpacket), are changed by the transmitted corrupting signal. Alternativelyor in addition, the corrupting signal may change a value in one or morefields in the frame (or packet), rendering this field non-legitimateaccording to the agreed upon or used communication protocol. In oneexample, such as in a CAN protocol, the corrupting signal may generate asequence of six or more consecutive identical bits when received by thedevices over the bus, known to be a standard CAN error frame. Further,one or more defined flags in the message, such as error flag may be setby the corrupting signal. When the message uses recessive (‘1’) anddominant (‘0’) (non-recessive) bits, the corrupting signal may convert arecessive bit (or multiple bits) to a dominant one, or may convert adominant bit (or multiple bits) to a recessive one.

Error correction. Error correction refers to the detection of errors andreconstruction of the original, error-free data, and in many casesenables reconstruction of the original data. Error Correcting Code (ECC)is used for controlling errors in data over unreliable or noisycommunication channels. The principle is based on that the senderencodes the message with a redundant in the form of an ECC. Theredundancy allows the receiver to detect a limited number of errors thatmay occur anywhere in the message, and often to correct these errorswithout retransmission. ECC gives the receiver the ability to correcterrors without needing a reverse channel to request retransmission ofdata, but at the cost of a fixed, higher forward channel bandwidth.

The two main categories of ECC codes are block codes and convolutionalcodes. Block codes work on fixed-size blocks (packets) of bits orsymbols of predetermined size. Practical block codes can generally behard-decoded in polynomial time to their block length. Convolutionalcodes work on bit or symbol streams of arbitrary length. They are mostoften soft decoded with the Viterbi algorithm, though other algorithmsare sometimes used. Viterbi decoding allows asymptotically optimaldecoding efficiency with increasing constraint length of theconvolutional code, but at the expense of exponentially increasingcomplexity. A convolutional code that is terminated is also a ‘blockcode’ in that it encodes a block of input data, but the block size of aconvolutional code is generally arbitrary, while block codes have afixed size dictated by their algebraic characteristics. Types oftermination for convolutional codes include “tail-biting” and“bit-flushing”.

Error correction may generally be realized in two different ways:Automatic Repeat Request (ARQ) (sometimes also referred to as backwarderror correction)—This is an error control technique whereby an errordetection scheme is combined with requests for retransmission oferroneous data. Every block of data received is checked using the errordetection code used, and if the check fails, retransmission of the datais requested—this may be done repeatedly, until the data can beverified. In Forward error correction (FEC): The sender encodes the datausing an Error-Correcting Code (ECC) prior to transmission. Theadditional information (redundancy) added by the code is used by thereceiver to recover the original data. In general, the reconstructeddata is what is deemed the “most likely” original data. ARQ and FEC maybe combined, such that minor errors are corrected withoutretransmission, and major errors are corrected via a request forretransmission: this is called hybrid automatic repeat-request (HARQ). Arandom-error-correcting code based on minimum distance coding canprovide a strict guarantee on the number of detectable errors, but itmay not protect against a preimage attack. A repetition code, describedin the section below, is a special case of error-correcting code:although rather inefficient, a repetition code is suitable in someapplications of error correction and detection due to its simplicity.

An apparatus for protecting a vehicle electronic system is disclosed inU.S. Patent Application Publication No. 2015/0020152 to Litichever etal. entitled: “Security system and method for protecting a vehicleelectronic system”, which is incorporated in its entirety for allpurposes as if fully set forth herein. The protecting is by selectivelyintervening in the communications path in order to prevent the arrivalof malicious messages at ECUs, in particular at the safety criticalECUs. The security system includes a filter, which prevents illegalmessages sent by any system or device communicating over a vehiclecommunications bus from reaching their destination. The filter may, atits discretion according to preconfigured rules, send messages as is,block messages, change the content of the messages, requestauthentication or limit the rate such messages can be delivered, bybuffering the messages and sending them only in preconfigured intervals.

A system for providing security to an in-vehicle communication networkis disclosed in U.S. Patent Application Publication No. 2015/0195297 toBEN NOON et al. entitled: “Global automotive safety system”, which isincorporated in its entirety for all purposes as if fully set forthherein. The system comprising: a data monitoring and processing hub; andat least one module configured to monitor messages in communicationtraffic propagating in a vehicle's in-vehicle network, the networkhaving a bus and at least one node connected to the bus, the modulecomprising: a communication interface configured to supportcommunication with the hub; a memory having software comprising datacharacterizing messages that the at least one node transmits andreceives during normal operation of the node; at least one communicationport via which the module receives and transmits messages configured tobe connected to a portion of the in-vehicle network; a processor thatprocesses messages received via the port from the portion of thein-vehicle network responsive to the software in the memory to: identifyan anomalous message in the received messages indicative of exposure ofthe in-vehicle network to damage from a cyber-attack; determine anaction to be taken by the module that affects the anomalous message; andtransmit data responsive to the anomalous message to the hub forprocessing by the hub via the communication interface.

A system and method for providing security to a network may includemaintaining, by a processor, a model of an expected behavior of datacommunications over the in-vehicle communication network are disclosedin U.S. Patent Application Publication No. 2016/0381059 to GALULA et al.entitled: “SYSTEM AND METHOD FOR TIME BASED ANOMALY DETECTION IN ANIN-VEHICLE COMMUNICATION NETWORK”, which is incorporated in its entiretyfor all purposes as if fully set forth herein. The method comprisesreceiving, by the processor, a message sent over the network;determining, by the controller, based on the model and based on a timingattribute of the message, whether or not the message complies with themodel; and if the message does not comply with the model thenperforming, by the processor, at least one action related to themessage.

A system and method for providing security to a network are disclosed inU.S. Patent Application Publication No. 2016/0381055 to GALULA et al.entitled: “SYSTEM AND METHOD FOR PROVIDING SECURITY TO A COMMUNICATIONNETWORK”, which is incorporated in its entirety for all purposes as iffully set forth herein. The method may include identifying a messagesent over a network, the message related to a data transfer from aninitiator to a target node, and transmitting, over the network, at leastone disruptive message that causes the data transfer to fail.

A system and method for detection of at least one cyber-attack on one ormore vehicles are disclosed in U.S. Patent Application Publication No.2017/0230385 to Ruvio et al. entitled: “Vehicle correlation system forcyber attacks detection and method thereof”, which is incorporated inits entirety for all purposes as if fully set forth herein. The systemand method including steps of transmitting and/or receiving by a firston-board agent module installed within one or more vehicles and/or asecond on-board agent module installed within road infrastructure and ina range of communication with said first on-board agent module metadatato and/or from an on-site and/or remote cloud-based detection serverincluding a correlation engine; detecting cyberattacks based oncorrelation calculation between the metadata received from one or morefirst agent module installed within vehicles and/or from one or moresecond agent modules installed within road infrastructure; indicating aprobability of a cyber-attack against one or more vehicle based oncorrelation calculation; initiating blocking of vehicle-to-vehiclecommunication to present and/or stop a spread of an identified threat.

A device for detection and prevention of an attack on a vehicle via itscommunication channels is disclosed in U.S. Patent ApplicationPublication No. 2015/0271201 to Ruvio et al. entitled: “Device fordetection and prevention of an attack on a vehicle”, which isincorporated in its entirety for all purposes as if fully set forthherein. The device having: an input-unit configured to collect real-timeand/or offline data from various sources such as sensors, network basedservices, navigation applications, the vehicles electronic controlunits, the vehicle's bus-networks, the vehicle's subsystems, and onboard diagnostics; a database, for storing the data; a detection-unit incommunication with the input-unit; and an action-unit, in communicationwith the detection unit, configured for sending an alert via thecommunication channels and/or prevent the attack, by breaking orchanging the attacked communication channels. The detection-unit isconfigured to simultaneously monitor the content, the meta-data and thephysical-data of the data and detect the attack.

A connection detection apparatus is disclosed in U.S. Patent ApplicationPublication No. 2014/0380416 to Adachi entitled: “Connection detectionapparatus and in-vehicle relay apparatus”, which is incorporated in itsentirety for all purposes as if fully set forth herein. The apparatusincludes a gateway to which communication lines are connected, and whichdetects whether an unauthorized communication device has been connectedto the communication lines. The gateway samples a signal several timesfrom each of the communication lines, and generates waveforminformation, such as an eye pattern in which the waveforms aresuperimposed on one another. Furthermore, the gateway has stored normalwaveform information therein, such as a mask generated based on the eyepattern at normal times. The gateway compares the generated waveforminformation with the stored waveform information, and recognizes thatthe waveform information is abnormal if it does not sufficiently matchthe normal waveform information. If the waveform information isabnormal, it is determined that an unauthorized communication device hasbeen connected to one or more of the communication lines.

A system and method for detecting an intrusion or a bug in a vehicledata transmission system is disclosed in U.S. Pat. No. 8,955,130 toKalintsev et al. entitled: “Method for protecting vehicle datatransmission system from intrusions”, which is incorporated in itsentirety for all purposes as if fully set forth herein. Ahardware-software complex (HSC) is used to find a bug or intrusiondevice in a vehicle electronic system. The HSC is connected to CAN-busesin the vehicle and also scans radio waves, which can be used to transmitdata to a bug. This complex is a self-teaching CAN-system used tomonitor and block harmful commands in the vehicle. Each vehicle (of eachmodel, type and settings) has its own reference bus data (parameters),which is used to detect added modules and malicious data sent over thevehicle's CAN bus.

A method for detecting threats or attacks on an automobile network, isdisclosed in U.S. Pat. No. 9,401,923 to Valasek et al. entitled:“Electronic system for detecting and preventing compromise of vehicleelectrical and control systems”, which is incorporated in its entiretyfor all purposes as if fully set forth herein. The automobile network isconnected to a plurality of electronic components and an attackmonitoring unit including a processor, the method including: monitoring,by the processor of the attack monitoring unit, data messagestransmitted on the automobile network; determining, by the processor ofthe attack monitoring unit, whether at least one data message among thedata messages transmitted on the mobile network is a threat to one ormore of the plurality of electronic components on the automobilenetwork; and when it is determined, by the processor, that the at leastone data message is a threat, performing at least one action based onthe threat.

Methods and apparatus for physical layer security of a networkcommunications link are disclosed in U.S. Pat. No. 7,752,672 to Karam etal. entitled: “Methods and apparatus for physical layer security of anetwork communications link”, which is incorporated in its entirety forall purposes as if fully set forth herein. A communications port of anetwork communications device maintains capability informationindicating that under normal operating conditions a communications linkis capable of operating in a secure mode in which communications signalsof the communications link are unintelligible to an intruder having anunauthorized physical connection (e.g. tap) to the communications link.During operation, the port detects occurrence of a link event of a typethat can invoke an automatic communications-mode control mechanism tochange the operating of the communications link to a non-secure mode inwhich communications signals of the communications link are intelligibleto such an intruder. An example is Ethernet auto-negotiation, which canchange from relatively secure 1000BaseT signaling to relativelynon-secure 10/100BaseT signaling. Based on the capability information,the port responds to the link event by preventing the automaticcommunications mode control mechanism from changing the operating of thecommunications link to the non-secure mode.

Processor. The term “processor” is used herein to include, but notlimited to, any integrated circuit or any other electronic device (orcollection of electronic devices) capable of performing an operation onat least one instruction, including, without limitation, amicroprocessor (μP), a microcontroller (μC), a Digital Signal Processor(DSP), or any combination thereof. A processor may further be a ReducedInstruction Set Core (RISC) processor, a Complex Instruction SetComputing (CISC) microprocessor, a Microcontroller Unit (MCU), or aCISC-based Central Processing Unit (CPU). The hardware of the processormay be integrated onto a single substrate (e.g., silicon “die”), ordistributed among two or more substrates.

A non-limiting example of a processor may be 80186 or 80188 availablefrom Intel Corporation located at Santa Clara, Calif., USA. The 80186and its detailed memory connections are described in the manual“80186/80188 High-Integration 16-Bit Microprocessors” by IntelCorporation, which is incorporated in its entirety for all purposes asif fully set forth herein. Other non-limiting example of a processor maybe MC68360 available from Motorola Inc. located at Schaumburg, Ill.,USA. The MC68360 and its detailed memory connections are described inthe manual “MC68360 Quad Integrated Communications Controller—User'sManual” by Motorola, Inc., which is incorporated in its entirety for allpurposes as if fully set forth herein. While exampled above regarding anaddress bus having an 8-bit width, other widths of address buses arecommonly used, such as the 16-bit, 32-bit and 64-bit. Similarly, whileexampled above regarding a data bus having an 8-bit width, other widthsof data buses are commonly used, such as 16-bit, 32-bit and 64-bitwidth. In one example, the processor consists of, comprises, or is partof, Tiva™ TM4C123GH6PM Microcontroller available from Texas InstrumentsIncorporated (Headquartered in Dallas, Tex., U.S.A.), described in adata sheet published 2015 by Texas Instruments Incorporated[DS-TM4C123GH6PM-15842.2741, SPMS376E, Revision 15842.2741 June 2014],entitled: “Tiva™ TM4C123GH6PM Microcontroller—Data Sheet”, which isincorporated in its entirety for all purposes as if fully set forthherein, and is part of Texas Instrument's Tiva™ C Seriesmicrocontrollers family that provide designers a high-performance ARM®Cortex™-M-based architecture with a broad set of integrationcapabilities and a strong ecosystem of software and development tools.Targeting performance and flexibility, the Tiva™ C Series architectureoffers an 80 MHz Cortex-M with FPU, a variety of integrated memories andmultiple programmable GPIO. Tiva™ C Series devices offer consumerscompelling cost-effective solutions by integrating application-specificperipherals and providing a comprehensive library of software toolswhich minimize board costs and design-cycle time. Offering quickertime-to-market and cost savings, the Tiva™ C Series microcontrollers arethe leading choice in high-performance 32-bit applications. Targetingperformance and flexibility, the Tiva™ C Series architecture offers an80 MHz Cortex-M with FPU, a variety of integrated memories and multipleprogrammable GPIO. Tiva™ C Series devices offer consumers compellingcost-effective solutions.

Compression. Data compression, also known as source coding and bit-ratereduction, involves encoding information using fewer bits than theoriginal representation. Compression can be either lossy or lossless.Lossless compression reduces bits by identifying and eliminatingstatistical redundancy, so that no information is lost in losslesscompression. Lossy compression reduces bits by identifying unnecessaryinformation and removing it. The process of reducing the size of a datafile is commonly referred to as a data compression. A compression isused to reduce resource usage, such as data storage space ortransmission capacity. Data compression is further described in aCarnegie Mellon University chapter entitled: “Introduction to DataCompression” by Guy E. Blelloch, dated Jan. 31, 2013, and in a ThirdEdition of a book entitled: “Introduction to Data Compression” authoredby Khalid Sayood of the University of Nebraska [ISBN 13:978-0-12-620862-7], published 2006 by Elsevier Inc., which are bothincorporated in their entirety for all purposes as if fully set forthherein.

In a scheme involving lossy data compression, some loss of informationis acceptable. For example, dropping of a nonessential detail from adata can save storage space. Lossy data compression schemes may beinformed by research on how people perceive the data involved. Forexample, the human eye is more sensitive to subtle variations inluminance than it is to variations in color. JPEG image compressionworks in part by rounding off nonessential bits of information. There isa corresponding trade-off between preserving information and reducingsize. A number of popular compression formats exploit these perceptualdifferences, including those used in music files, images, and video.

Lossy image compression is commonly used in digital cameras, to increasestorage capacities with minimal degradation of picture quality.Similarly, DVDs use the lossy MPEG-2 Video codec for video compression.In lossy audio compression, methods of psychoacoustics are used toremove non-audible (or less audible) components of the audio signal.Compression of human speech is often performed with even morespecialized techniques; speech coding, or voice coding, is sometimesdistinguished as a separate discipline from audio compression. Differentaudio and speech compression standards are listed under audio codecs.Voice compression is used in Internet telephony, for example, and audiocompression is used for CD ripping and is decoded by audio player.

Lossless compression is a class of data compression algorithms thatallows the original data to be perfectly reconstructed from thecompressed data, and 1 algorithms usually exploit statistical redundancyto represent data more concisely without losing information, so that theprocess is reversible. By contrast, lossy compression permitsreconstruction only of an approximation of the original data, thoughusually with improved compression rates (and therefore reduced filesizes). Lossless compression is used in cases where it is important thatthe original and the decompressed data be identical, or where deviationsfrom the original data would be unfavourable. Typical examples areexecutable programs, text documents, and source code. Some image fileformats, like PNG or GIF, use only lossless compression, while otherslike TIFF and MNG may use either lossless or lossy methods. Losslessaudio formats are most often used for archiving or production purposes,while smaller lossy audio files are typically used on portable playersand in other cases where storage space is limited or exact replicationof the audio is unnecessary.

Most lossless compression programs do two things in sequence: the firststep generates a statistical model for the input data, and the secondstep uses this model to map input data to bit sequences in such a waythat “probable” (e.g. frequently encountered) data will produce shorteroutput than “improbable” data. The primary encoding algorithms used toproduce bit sequences are Huffman coding (also used by DEFLATE) andarithmetic coding. Arithmetic coding achieves compression rates close tothe best possible for a particular statistical model, which is given bythe information entropy, whereas Huffman compression is simpler andfaster but produces poor results for models that deal with symbolprobabilities close to 1. There are two primary ways of constructingstatistical models: in a static model, the data is analyzed and a modelis constructed, then this model is stored with the compressed data. Thisapproach is simple and modular, but has the disadvantage that the modelitself can be expensive to store, and also that it forces using a singlemodel for all data being compressed, and so performs poorly on filesthat contain heterogeneous data. Adaptive models dynamically update themodel as the data is compressed. Both the encoder and decoder begin witha trivial model, yielding poor compression of initial data, but as theylearn more about the data, performance improves. Most popular types ofcompression used in practice now use adaptive coders.

Lossless compression typically is based on real-world data that hasstatistical redundancy. The Lempel-Ziv (LZ) compression methods areamong the most popular algorithms for lossless storage. DEFLATE is avariation on LZ optimized for decompression speed and compression ratio,and is used in PKZIP, Gzip and PNG. The LZW (Lempel-Ziv-Welch) method iscommonly used in GIF images, and is described in IETF RFC 1951. The LZmethods use a table-based compression model where table entries aresubstituted for repeated strings of data. For most LZ methods, thistable is generated dynamically from earlier data in the input. The tableitself is often Huffman encoded (e.g., SHRI, LZX). Typical modernlossless compressors use probabilistic models, such as prediction bypartial matching.

Lempel-Ziv-Welch (LZW) is an example of lossless data compressionalgorithm created by Abraham Lempel, Jacob Ziv, and Terry Welch. Thealgorithm is simple to implement, and has the potential for very highthroughput in hardware implementations. It was the algorithm of thewidely used Unix file compression utility compress, and is used in theGIF image format. The LZW and similar algorithms are described in U.S.Pat. No. 4,464,650 to Eastman et al. entitled: “Apparatus and Method forCompressing Data Signals and Restoring the Compressed Data Signals”, inU.S. Pat. No. 4,814,746 to Miller et al. entitled: “Data CompressionMethod”, and in U.S. Pat. No. 4,558,302 to Welch entitled: “High SpeedData Compression and Decompression Apparatus and Method”, which are allincorporated in their entirety for all purposes as if fully set forthherein.

A class of lossless data compression algorithms is based on usingdictionaries, and operates by searching for matches between the text tobe compressed and a set of strings contained in a data structure (calledthe ‘dictionary’) maintained by the encoder. When the encoder finds sucha match, it substitutes a reference to the string's position in the datastructure.

Some dictionary coders use a ‘static dictionary’, one whose full set ofstrings is determined before coding begins and does not change duringthe coding process. This approach is most often used when the message orset of messages to be encoded is fixed and large. A dictionary is oftenbuilt from redundancy extracted from a data environment (various inputstreams) which dictionary is then used statically to compress a furtherinput stream. For example, a dictionary may be built from old Englishtexts then is used to compress a book. More common are methods where thedictionary starts in some predetermined state, but the contents changeduring the encoding process, based on the data that has already beenencoded.

Both the LZ77 and LZ78 algorithms work on this principle, where in LZ77,a circular buffer called the “sliding window” holds the last N bytes ofdata processed, which serves as the dictionary, effectively storingevery substring that has appeared in the past N bytes as dictionaryentries. Instead of a single index identifying a dictionary entry, twovalues are needed: the length, indicating the length of the matchedtext, and the offset (also called the distance), indicating that thematch is found in the sliding window starting offset bytes before thecurrent text. LZ78 uses a more explicit dictionary structure; at thebeginning of the encoding process, the dictionary only needs to containentries for the symbols of the alphabet used in the text to becompressed, but the indexes are numbered in order to leave spaces formany more entries. At each step of the encoding process, the longestentry in the dictionary that matches the text is found, and its index iswritten to the output; the combination of that entry and the characterthat followed it in the text is then added to the dictionary as a newentry. An example of a dictionary-based compression is described in anUniversity of Michigan paper entitled: “Dictionary-Based Compression forLong Time-Series Similarity” by Willis Lang, Michael Morse, and JigneshM. Patel, downloaded from http://pages.cs.wisc.edu/ on August 2014,which is incorporated in its entirety for all purposes as if fully setforth herein.

A security system for protecting a vehicle electronic system isdisclosed in U.S. Pat. No. 9,965,636 to Litichever et al. entitled:“Security system and method for protecting a vehicle electronic system”,which is incorporated in its entirety for all purposes as if fully setforth herein. The security system selectively intervening in thecommunications path in order to prevent the arrival of maliciousmessages at ECUs, in particular at the safety critical ECUs. Thesecurity system includes a filter which prevents illegal messages sentby any system or device communicating over a vehicle communications busfrom reaching their destination. The filter may, at its discretionaccording to preconfigured rules, send messages as is, block messages,change the content of the messages, request authentication or limit therate such messages can be delivered, by buffering the messages andsending them only in preconfigured intervals.

A method of real-time data security of a communications bus is disclosedin U.S. Pat. No. 10,140,450 to Litichever et al. entitled: “Vehiclecommunications bus data security”, which is incorporated in its entiretyfor all purposes as if fully set forth herein. The method comprising thesteps of: reading at least an early portion of a message beingtransmitted over a communications bus, determining whether the messageis suspicious, according to at least one rule applied on the read earlyportion of the message, and upon determining that the message issuspicious, corrupting at least a part of the message.

An analyzer for monitoring a configuration of a wired network mediumthat is used for communication between multiple devices is described inPatent Cooperation Treaty (PCT) International Patent Application WO2018104929A1 to Litichever et al. entitled: “System and method for usingsignal waveform analysis for detecting a change in a wired network”,which is incorporated in its entirety for all purposes as if fully setforth herein. The configuration change includes an additional devicetapping to the medium for eavesdropping, or the substituting one of thedevices. The analyzer is connected to the medium for receiving, storing,and analyzing waveforms of the physical-layer signals propagated overthe medium. The analysis includes comparing the received signals toreference signals, and notifying upon detecting a difference accordingto pre-set criteria. The analysis may be time or frequency-domain based,and may use a feed-forward Artificial Neural Network (ANN). The wirednetwork may be an automotive or in-vehicle network, PAN, LAN, MAN, orWAN, may use balanced or unbalanced signaling, and may be configured aspoint-to-point or multi-point topology. The analyzer may be connected atan end of the medium, and may be integrated with one of the devices.

An apparatus and a method for processing sensor data for a vehicle usingan unified data format eXtensible Markup Language in process of datacommunication between various vehicle sensors and a vehicle applicationsystem are disclosed in U.S. Pat. No. 8,909,412 to Park et al. entitled:“Apparatus and method for processing sensor data for vehicle usingextensible markup language”, which is incorporated in its entirety forall purposes as if fully set forth herein. The apparatus or the methodfacilitates transmit and receive data processing in terms of a vehiclenetwork of the sensors and the application system are provided. Theapparatus for processing the sensor data for the vehicle using the XMLincludes a plurality of vehicle sensors installed inside the vehicle fordetecting a change of physical quantity and providing a detectionsignal; a sensor transducer for converting the detection signal of thevehicle sensors to an electrical analog signal; a signal conditioningunit for amplifying the electrical analog signal to a measurable signal;an Analog/Digital Converter (ADC) for converting the amplified analogsignal to sensor data of a digital signal; a frame generator forgenerating and providing the sensor data converted to the digital signalper frame; and a sensor data converter comprising a Dynamic dataExchange Channel (DEC) for batch-processing the sensor data input fromthe frame generator per frame, in an XML format. The DEC of the sensordata converter defines a structure of the sensor data using a schema ofthe XML and converts the sensor data format to the XML format at thesame time.

Atlas implemented based on the LEON3 softcore processor, includingtoolchain extensions for developers, is disclosed in a paper entitled:“Atlas: Application Confidentiality in Compromised Embedded Systems” byPieter Maene, Johannes Gotzfried, Tilo Muller, Ruan de Clercq, FelixFreiling and Ingrid Verbauwhede published July 2018 in IEEE Transactionson Dependable and Secure Computing PP(99):1-1 [DOI:10.1109/TDSC.2018.2858257], which is incorporated in its entirety forall purposes as if fully set forth herein. Due to the requirements ofthe Internet-of-Things, modern embedded systems have become increasinglycomplex, running different applications. In order to protect theirintellectual property as well as the confidentiality of sensitive datathey process, these applications have to be isolated from each other.Traditional memory protection and memory management units provide suchisolation, but rely on operating system support for their configuration.However, modern operating systems tend to be vulnerable and cannotguarantee confidentiality when compromised. The paper present Atlas, ahardware-based security architecture, complementary to traditionalmemory protection mechanisms, ensuring code and data confidentialitythrough transparent encryption, even when the system software has beenexploited. Atlas relies on its zero-software trusted computing base toprotect against system-level attackers and also supports secure sharedmemory. The described FPGA-based evaluation shows minimal cycle overheadat the cost of a reduced maximum frequency.

A method for selectively pre-processing and recording sensor data forengineering testing purposes in vehicles. In order to condense data,methodologies from the domain of sensor networks and stream processingare applied, which results in a reduction of the quantity of data, whilemaintaining information quality, is described in a paper entitled:“Flexible In-Vehicle Stream Processing with Distributed AutomotiveControl Units for Engineering and Diagnosis” by Hendrik Schweppe, ArminZimmermann, and Daniel Grill, published June 2008 in a conference: IEEEThird International Symposium on Industrial Embedded Systems—SIES 2008,Montpellier/La Grande Motte, France, 11-13 Jun. 2008 [DOI:10.1109/SIES.2008.4577683], which is incorporated in its entirety forall purposes as if fully set forth herein. A situation-dependentmodification of recording parameters allows for a detailed profiling ofvehicle-related errors. We developed a data-flow oriented model, inwhich data streams are connected by processing nodes. These nodes filterand aggregate the data and can be connected in nearly any order, whichpermits a successive composition of the aggregation and recordingstrategy. The integration with an event-condition-action model providesadaptability of the processing and recording, depending on the state ofthe vehicle. In a proof-of-concept system, which we implemented on topof the automotive diagnostic protocols KWP and UDS, the feasibility ofthe approach was shown. The target platform was an embedded on-boardcomputer that is connected to the OBD-II interface of the vehicle. Asthe scope of recording can be adjusted flexibly, the recording systemcan not only be used for diagnostic purposes, but also serves objectivesin development, quality assurance, and even marketing.

Method for generating an output of a random source of a random generatoris disclosed in U.S. Patent Application Publication No. 2015/0193205 toBoehl entitled: “A method for generating an output of a random source”,which is incorporated in its entirety for all purposes as if fully setforth herein. In the method the random source is sampled using at leasttwo sampling units in such a way that an output signal is generated ineach case, and the output signals of each sampling unit are eachprocessed by a processing unit.

A transmission of binary data over a network (16, 17) between atransmission host (A) and a receiving host (B) is described in PatentCooperation Treaty (PCT) International Patent Application WO 2001065439A1 to Roy et al. entitled: “A technique for data compression by decodingbinary encoded data”, which is incorporated in its entirety for allpurposes as if fully set forth herein. The transmission host (A)receives packets of data including data in a first format (34) which maybe ASCII formatted and contain 6 bits-per-byte words, and including datawhich had an original binary format (35) containing greater than 6bits-per-byte words (such as 8 bits-per-byte) and which has been encoded(37) (such as Unencoded) to 6 bits-per-byte words. The transmission host(A) searches the packets and identifies the encoded data (37) andreverse codes (38) the encoded data to its original binary format (35),before transmitting the data on a suitable network transmission media(16, 17) that can transmit both ASCII formatted data (34) and data (35)having greater than 6 bit-per-byte formats. The transmission host (A)also includes an application packet demultiplexer (21) for separatingthe incoming data according its application such as HTTP, NNTP, FTP,etc. The transmitting host (A) includes an identifier in the packets foridentifying the reverse coded data. The receiving host responds to theidentifier and may encode the previously reverse coded data (B).

An apparatus and method for determining whether a text is deceptive isdescribed in Patent Cooperation Treaty (PCT) International PatentApplication WO 2011139687A1 to Chandramouli et al. entitled: “Systemsand methods for automatically detecting deception in humancommunications expressed in digital form”, which is incorporated in itsentirety for all purposes as if fully set forth herein. The apparatusand method have a computer programmed with software that automaticallyanalyzes a text message in digital form for deceptiveness by at leastone of statistical analysis of text content to ascertain and evaluatepsycho-linguistic cues that are present in the text message, IPgeo-location of the source of the message, gender analysis of the authorof the message, authorship similarity analysis, and analysis to detectcoded/camouflaged messages. The computer has access to truth dataagainst which the veracity of the text message can be compared and agraphical user interface through which a user of the system can controlthe system and receive results concerning the deceptiveness of the textmessage analyzed by the system. The computer may be connectable to theInternet and may obtain the text to be analyzed either under the controlof the user or automatically.

The eXtended Ciphertext Block Chaining (XCBC) and the eXtendedElectronic Codebook (XECB) encryption schemes or modes of encryptionthat can detect encrypted-message forgeries with high probability evenwhen used with typical noncryptographic Manipulation Detection Code(MDC) functions (e.g., bitwise exclusive-or and cyclic redundancy code(CRC) functions) is presented in a paper by Virgil D. Gligor andPompiliu Donescu entitled: “Fast Encryption and Authentication: XCBCEncryption and XECB Authentication Modes” published 2002 bySpringer-Verlag Berlin Heidelberg, which is incorporated in its entiretyfor all purposes as if fully set forth herein. These modes detectencrypted-message forgeries at low cost in performance, power, andimplementation, and preserve both message secrecy and integrity in asingle pass over the message data. Their performance and security scaledirectly with those of the underlying block cipher function. The paperalso presents the XECB message authentication (XECB-MAC) modes that haveall the operational properties of the XOR-MAC modes (e.g., fullyparallel and pipelined operation, incremental updates, and out-of-orderverification), and have better performance. They are intended for useeither stand-alone or with encryption modes that have similar properties(e.g., counter-based XOR encryption). However, the XECB-MAC modes havehigher upper bounds on the probability of adversary's success inproducing a forgery than the XOR-MAC modes.

A method for run time zero byte compression of data on a communicationbus of a vehicle includes determining a number of zero bytes provided ina data frame, is disclosed in U.S. Pat. No. 9,219,499 to Nasserentitled: “Run time compression method for a vehicle communication bus”,which is incorporated in its entirety for all purposes as if fully setforth herein. When there are enough zero bytes, an encoding byte isgenerated that maps the locations of the zero bytes in the data frame. Adata length code related to the number of non-zero data bytes and theencoding byte is provided in a device header. The data length code has avalue less than an uncompressed data frame. The compressed data frame istransmitted with the encoding byte and the uncompressed non-zero databytes. To decompress the compressed data frame, the encoding byte mapsthe locations of the zero bytes for a data frame. The non-zero databytes are then provided at the proper locations to recreate the dataframe.

Systems and methods for compressing data in a network systemcommunicated across a network are disclosed in U.S. Pat. No. 9,172,771to Gross et al. entitled: “System and methods for compressing data basedon data link characteristics”, which is incorporated in its entirety forall purposes as if fully set forth herein. The network system maydetermine a data link characteristic for a data link between a sourceand a destination. A compression algorithm may be selected from among aplurality of compression algorithms based on the data linkcharacteristic. A chunk of data may be compressed, using the selectedcompression algorithm, to be communicated over the data link. Acompression ratio of the compressed chunk and the chunk uncompressed maybe compared to a compression threshold. The compressed chunk may beprovided, using the control circuitry, if the compression ratio isgreater or equal to the compression threshold. The chunk uncompressedmay be provided if the first compression ratio is less than to the firstcompression threshold.

A data compression and decompression method and a data processingapparatus are disclosed in European Patent Application No. EP 2131501A1to Richert entitled: “Data compression and decompression method and dataprocessing apparatus”, which is incorporated in its entirety for allpurposes as if fully set forth herein. In a data compression method,data is retrieved from a data block (160). A packet type is selectedfrom a plurality of packet types based on whether the data includes apredetermined number of repetitions of a data sequence (169). A datapacket (171-173, 191) is generated from the data, the data packet(171-173, 191) including control information (174, 175a, 175c, 176,177a, 177c, 178) set based on the packet type and size information (174,175b, 177b) set based on a storage space containing the controlinformation (174, 175a, 175c, 176, 177a, 177c, 178).

In consideration of the foregoing, it would be an advancement to providea method or a system for Layer-2 based compression that is based onfixed length block or frame, is lossless, is stateless, or anycombination thereof. Such compression may be simple, secure,cost-effective, reliable, easy to use, use minimally added overhead,minimally increases CPU workload or processing time, has a minimum partcount, minimum hardware, and/or uses existing and available components,protocols, programs and applications for providing better security andadditional functionalities, and provides a better user experience.

SUMMARY

A method herein may provide a lossless and stateless compression scheme.Any method herein may be used with a group of multiple frames that maybe according to a first protocol and may include, such as in a fixedlocation in the frames, a fixed length payload consisting of M bits, andthe number of values in the first payload may be equal to, or less than,2^(N) possible values. Any method herein may comprise receiving aplurality of frames according to a second protocol, that may include afixed length payload consisting of N bits, and for each of a receivedfirst frame out of the plurality of frames: identifying and extracting afirst N-bit payload from the received first frame; mapping the firstpayload to a second payload consisting of M bits, wherein M>N and themapping comprises associating a single N-bit value to a single M-bitvalue; constructing a second frame according to the first protocol thatincludes the second M-bit payload and is part of the group; and using orsending the constructed second frame.

Any method or steps herein may be performed in a first device, the firstdevice may comprise software and a processor for executing the software,and part of, or all of, any steps herein may be performed by theprocessor. Any method or steps herein may be used with a second devicedistinct from the first device, and any sending herein may comprisesending the second frame to the second device.

Any device herein, such as the first or second device, may consist of,or may comprise, a vehicle. Any vehicle herein may be a ground vehicleadapted to travel on land, such as a bicycle, a car, a motorcycle, atrain, an electric scooter, a subway, a train, a trolleybus, and a tram.Alternatively or in addition, the vehicle may be a buoyant or submergedwatercraft adapted to travel on or in water, and the watercraft may be aship, a boat, a hovercraft, a sailboat, a yacht, or a submarine.Alternatively or in addition, the vehicle may be an aircraft adapted tofly in air, and the aircraft may be a fixed wing or a rotorcraftaircraft, such as an airplane, a spacecraft, a glider, a drone, or anUnmanned Aerial Vehicle (UAV).

Any device herein, such as the first or second device, may consist of,may be integrated with, or may be part of, an Electronic Control Unit(ECU) in a vehicle. Any Electronic Control Unit (ECU) herein may beselected from the group consisting of Electronic/engine Control Module(ECM), Engine Control Unit (ECU), Powertrain Control Module (PCM),Transmission Control Module (TCM), Brake Control Module (BCM or EBCM),Central Control Module (CCM), Central Timing Module (CTM), GeneralElectronic Module (GEM), Body Control Module (BCM), Suspension ControlModule (SCM), Door Control Unit (DCU), Electric Power Steering ControlUnit (PSCU), Seat Control Unit, Speed Control Unit (SCU), TelematicControl Unit (TCU), Transmission Control Unit (TCU), Brake ControlModule (BCM; ABS or ESC), Battery management system, control unit, and acontrol module. Any method or ECU herein may further comprise executingsoftware, an operating-system, or a middleware, that may comprise, ormay use OSEK/VDX, International Organization for Standardization (ISO)17356-1, ISO 17356-2, ISO 17356-3, ISO 17356-4, ISO 17356-5, or AUTOSARstandard. Alternatively or in addition, the software may comprises, mayuse, or may be based on, an operating-system or a middleware, thatcomprises, or uses OSEK/VDX, International Organization forStandardization (ISO) 17356-1, ISO 17356-2, ISO 17356-3, ISO 17356-4,ISO 17356-5, or AUTOSAR standard. At least one of any received framesherein, such as the first frames, may comprise Q N-bit first payloads.Each of most of, or all of, the received first frames may comprisemultiple N-bit first payloads, and the identifying and extracting maycomprise identifying and extracting of the Q first N-bit payloads fromthe received first frame, and mapping the first payload to a secondpayload consisting of M bits. Any constructing herein may compriseconstructing multiple second frame according to the first protocol eachincluding respective one of the second M-bit payloads, and any using orsending herein may comprise using or sending each of the multipleconstructed second frames. The multiple constructed second frames may becarried or encapsulated using a standard protocol that may consist of,may include, may be based on, or may be according to, an Open SystemsInterconnection (OSI) Layer-3 or Layer-4 standard protocol, which mayconsist of, may include, may be based on, or may be according to, ISO15765-2:2004 ISO-TP (Transport. Layer) standard.

The first protocol may be identical to, similar to, or different from,the second protocol. Each of the first and second protocols may include,may be based on, or may be according to, an OSI Layer-2 protocol thatmay consist of, or may be part of, the first protocol, and may beidentical to, or different from, the OSI layer-2 protocol that mayconsist of, or may be part of, the second protocol. Any protocol herein,such as the first or the second protocol, may consist of, may include,may be based on, or may be according to, an Open Systems Interconnection(OSI) Layer-3 or Layer-4 standard protocol, that may consist of, mayinclude, may be based on, or may be according to, ISO 15765-2:2004ISO-TP (Transport Layer) standard.

Any ratio M/N herein may be equal to, may be less than, or may be higherthan, 1.1, 1.2, 1.5, 2, 2.5, 3, 3.5, 5, 7, 10, 15, 20, 30, 50, or 100.Alternatively or in addition, any ratio 2^(M)/2^(N)=2^(M-N) herein maybe equal to, may be less than, or may be higher than, 2, 4, 8, 16, 32,64, 128, 256, 512, 1024, or 2048. Any N or M herein may be equal to, maybe less than, or may be higher than, 4, 8, 12, 16, 32, 64, 128, 256,512, or 1024.

Any method herein may be used with a number Q, where Q>1 and Q<M. Anymapping herein may comprise calculating a value of at least one of the Mbits or locations of the second payload based on the values of Q−1locations or bits in the N bits or locations of the first payload. Anynumber Q herein may be 2, 3, 4, 5, 6, 8, 10, 12, 15, or 20, and anymethod herein may be repeated for all Q from 2 to M−1. Any calculatingherein may be based on, or may use, Boolean operation of the Q−1locations or bits. Any calculating may be repeated, and any calculatedvalue of the at least one of the M bits or locations may be used forcalculating another at least one of the M bits or locations. Any methodherein may be used with a function that maps values of Q−1 bits to Qbits. At least one of the received first frames may comprise a firstfield that may comprise the location of each of the at least one of theM bits or locations of the second payload and a respective second fieldthat may comprise a value for each of the at least one of the M bits orlocations, and any mapping herein may comprise calculating a value of atleast one of the M bits or locations of the second payload based on thevalue of the respective second field. The first or second field may becarried in a field defined by the second protocol, which may consist of,may employ, may use, may be based on, or may be compatible with, aController Area Network (CAN), and wherein the first or second fieldconsists of, employs, uses, is based on, or is compatible with, a DataLength Code (DLC) field.

Any calculating herein may comprise mapping the value of the Q−1locations or bits to a value of Q bits, and the Q bits may be assignedto Q locations or bits in the M bits or locations of the second payload.Any constructing herein, such as the construction of the first frame forat least one of the received first frames, may comprise generating asecond field that may comprise the location of at least one of the atleast one of the M bits or locations of the second payload and a thirdfield that may comprise a respective value of the at least one of the Mbits or locations of the second payload. The second or third field maybe carried in a field defined by the second protocol, which may consistof, may employ, may use, may be based on, or may be compatible with, aController Area Network (CAN), and wherein the second or third fieldconsists of, employs, uses, is based on, or is compatible with, a DataLength Code (DLC) field.

Any method herein may further comprise receiving or obtaining anadditional frame according to the second protocol that may include apayload consisting of M bits; constructing an additional second frameaccording to the first protocol that may include the received M-bitunchanged payload; and using or sending the constructed additionalsecond frame. Alternatively or in addition, each of the receivedplurality of frames may include an indicator bit value. Any methodherein may further comprise receiving or obtaining an additional frameaccording to the second protocol that may include a payload consistingof M bits, responsive to the indicator bit value, constructing anadditional second frame according to the first protocol that may includethe received M-bit unchanged payload; and using or sending theconstructed additional second frame.

Any method herein may further comprise receiving or obtaining anadditional frame according to the second protocol that includes apayload consisting of M bits that is not part of the group of multipleframes; constructing an additional first frame according to the secondprotocol that includes the received M-bit unchanged payload; and usingor sending the constructed additional first frame. Any method herein mayfurther comprise generating an indicator bit and encapsulating theindicator bit in the additional first frame in a field defined by aprotocol, such as the second protocol. Any protocol herein, such as thesecond protocol may consist of, may employ, may use, may be based on, ormay be compatible with, a Controller Area Network (CAN), and any fieldherein may consists of, may employ, may use, may be based on, or may becompatible with, a Data Length Code (DLC) field.

Any method herein may be used with a memory that may have N addresslines or bits input and M data lines or bits output. Any mapping hereinmay comprise applying or writing the N-bit payload value as address andreading the M-bit value as output data. Any memory herein may be avolatile or a non-volatile memory, and may consist of, or may comprise,Hard Disk Drive (HDD), Solid State Drive (SSD), Random Access Memory(RAM), SRAM, Dynamic RAM (DRAM), Transistor RAM (TTRAM), Zero-capacitorRAM (Z-RAM), Read-Only Memory (ROM), Programmable ROM (PROM), EPROM,EEPROM, Flash-based memory, Compact Disc-ReWritable (CD-RW), DigitalVersatile Disk, or Digital Video Disk RW (DVD-RW), DVD+RW, DVD-RAMBD-RE, Compact Disc ROM (CD-ROM), BD-ROM, or DVD-ROM.

Alternatively or in addition, any mapping herein may use, or may bebased on, a combinatorial logic that may use digital logic gates. Anycombinatorial logic herein may comprise, or may consist of, aProgrammable Logic Device (PLD), that may comprise, may consist of, ormay be based on, Programmable Array Logic (PAL), Generic Array Logic(GAL), Complex Programmable Logic Device (CPLD), or Field-ProgrammableGate Array (FPGA). Any method herein may be used with software orfirmware and a processor that may execute the software or firmware, andany combinatorial logic herein may be calculated or performed by theprocessor.

Any mapping or associating herein may comprise calculating a Booleanlogic using logic gates for each one of the M bits or locations of thesecond payload, that may be based on one or more of the N bits orlocations of the first payload. At least one of the M bits or locationsof the second payload may be assigned as ‘0’ or ‘1’ for any receivedfirst payload. For example, the number of bits or locations from the Mbits or locations of the second payload that may be assigned as ‘0’ or‘1’ for any received first payload may be equal to, less than, or morethan, 2, 3, 4, 5, 7, 10, 15, 20, 30, 50, 70, or 100. Alternatively or inaddition, the number of bits or locations from the M bits or locationsof the second payload that may be assigned as ‘0’ or ‘1’ for anyreceived first payload may be equal to, less than, or more than, 1%, 2%,3%, 5%, 7%, 10%, 15%, 20%, 25%, 30%, 50%, 60%, or 70% of the M bits orlocations.

Alternatively or in addition, at least one of the M bits or locations ofthe second payload may be assigned the same or complement value of aselected location in the first payload. For example, at least 2, 3, 4,5, 7, 10, 15, 20, 30, 50, 70, or 100 of the M bits or locations of thesecond payload may be assigned the same or complement value of one ormore selected locations in the first payload. Alternatively or inaddition, at least at least 1%, 2%, 3%, 5%, 7%, 10%, 15%, 20%, 25%, 30%,50%, 60%, or 70% of the M bits or locations of the second payload may beassigned the same or complement value of one or more selected locationsin the first payload.

Alternatively or in addition, at least one of the M bits or locations ofthe second payload may be calculated using two of the N bits orlocations of the first payload. Alternatively or in addition, at leastone of the M bits or locations of the second payload may be calculatedusing three or more of the N bits or locations of the first payload.Alternatively or in addition, at least one of the M bits or locations ofthe second payload may be calculated using all of the N bits orlocations of the first payload, and each of the M bits or locations ofthe second payload may be calculated using all of the N bits orlocations of the first payload.

Any method or mapping (or associating) herein may be used with a storedset of coefficients (c₀, c₁, c₂, c₃, . . . c_(N-3), c_(N-2), c_(N-1),c_(N)), and at least one of the N bits or locations of the first payloadmay be calculated using the set of coefficients and the N bits orlocations of the first payload defined as (b₀, b₁, b₂, b₃, . . .b_(N-3), b_(N-2), b_(N-1)). Alternatively or in addition, any method ormapping herein may be used with M stored sets of coefficients, and eachof the N bits or locations of the first payload may be calculated usinga respective set of coefficients and the N bits or locations of thefirst payload. Further, any method or mapping herein may be used with amemory having N address lines or bits input and N+1 data lines or bitsoutput and storing all sets of coefficients, and any mapping herein maycomprise applying or writing the N-bit payload value as address andreading the N+1 bit value as coefficients output data.

Alternatively or in addition, at least one of the N bits or locations ofthe first payload may be calculated as (where the ‘⊕’ is a XOR operationand the ‘·’ is an AND operation):c⊕c ₀ ·b ₀ ⊕c ₁ ·b ₁ ⊕ . . . ⊕c _(N-1) ·b _(N-1)⊕c _(0,1) ·b ₀ ·b ₁ ⊕c _(0,2) ·b ₀ ·b ₂ ⊕ . . . ⊕c _(N-2,N-1) ·b _(N-2)·b _(N-1)⊕. . .c _(0,1, . . . ,N-2) ·b ₀ ·b ₁ . . . ·b _(N-2) ⊕ . . . ⊕c_(1,2, . . . ,N-2,N-1) ·b ₁ · . . . ·b _(N-2) ·b _(N-1).

Alternatively or in addition, at least one of the N bits or locations ofthe first payload may be calculated be means of the formula rewrittenwith some or all of other two-input Boolean operators, such as ‘AND’,‘OR’, NAND’, ‘NOR’, ‘XOR’, or ‘NXOR’, and which is equivalent to theabove formula with only ‘AND’ and ‘XOR’ operations. It is noted that the‘XOR’, and the ‘+’ (a modulo-2 summation) are the same for a one-bitnumber. Alternatively or in addition, at least one of the N bits orlocations of the first payload may be calculated asc₀*b₀+c₁*b₁+c₂*b₂+c₃*b₃+ . . .c_(N-3)*b_(N-3)+c_(N-2)*b_(N-2)+c_(N-1)*b_(N-1)+c_(N), wherein the ‘*’may be a two- input Boolean operator, such as ‘AND’, ‘OR’, NAND’, ‘NOR’,‘XOR’, or ‘NXOR’, and the ‘+’ operator may be a modulo-2 summation.

Alternatively or in addition, at least one of the N bits or locations ofthe first payload may be calculated be means of the formula rewrittenwith some or all of other two-input Boolean operators, such as ‘AND’,‘OR’, NAND’, ‘NOR’, ‘XOR’, or ‘NXOR’, and which is equivalent to theabove formula with only ‘AND’ and ‘XOR’ operations. It is noted that the‘XOR’, and the ‘+’ (a modulo-2 summation) are the same for a one-bitnumber. Alternatively or in addition, at least one of the N bits orlocations of the first payload is calculated as c₀⊕b₀+c₁⊕b₁+c₂⊕b₂+c₃⊕b₃+. . . c_(N-3)⊕b_(N-3)+c_(N-2)⊕b_(N-2)+c_(N-1)⊕b_(N-1)+c_(N), where the‘⊕’ is a XOR operation.

Any frame herein, such as part of, or all of, the received plurality offrames, may further include a code in a fixed length code field distinctfrom the fixed length payload consisting of N bits, and any methodherein may further comprise, for each of the received first frame thatmay include the code, identifying and extracting the code from anyreceived frame, such as the received first frame. The second protocolmay define a fixed length payload consisting of Q bits, and the codefield length may be equal to, or may be less than, Q−N. Further, N maybe equal to M (N=M) herein.

Any code or field herein may relate to, or may be associated with, anypayload herein such as the first or second payload. Any using or sendingherein may comprise using, or basing on, the extracted code from thecode field. Any code herein may comprise a metadata that may beaccording to, may be based on, or may be compatible with, eXtensibleMarkup Language (XML). Any method herein may be used with an errordetecting scheme, and any code herein may comprise an error detectingcode for detecting errors in the first or second payload, such as one ormore parity bits, a checksum, or a Cyclic Redundancy Code (CRC).Alternatively or in addition, any method herein may be used with aForward Error Correction (FEC) scheme, and any code herein may comprisean Error-Correcting Code (ECC) for correcting errors in the first orsecond payload. Alternatively or in addition, any method herein may beused with an authentication scheme, and any code herein may support, maybe part of, or may be associated with, the authentication scheme. Anyauthentication scheme herein may use, may comprise, may be based on, ormay be compatible with, Extensible Authentication Protocol (EAP), IEEE802.1X-2010 or IEEE 802.1AE-2006. Alternatively or in addition, any codeherein may support, may be part of, or may be associated with, a digitalsignature. Further, any authentication scheme herein may use, maycomprise, may be based on, or may be compatible with, AuthenticatedEncryption (AE) or Message Authentication Code (MAC), and any codeherein may support, may be part of, or may be associated with, a MessageAuthentication Code (MAC), a Keyed-Hash Message Authentication Code(HMAC), an Encryption Key identification, a frame counter, a Keyexchange information, or a random number. Any method herein may furthercomprise authenticating any received frame by using the code accordingto the authentication scheme. Any method herein may provide a losslessand stateless compression scheme. Any method herein may be used with agroup of multiple frames that may be according to a second protocol andmay include a fixed length payload consisting of M bits, and the numberof values in the first payload may be equal to, or may be less than,2^(N) possible values. Any method herein may comprise receiving orobtaining a plurality of frames. For each of a received second frame outof the plurality of frames, the method may comprise identifying andextracting a second M-bit payload from the received second frame; codingthe second payload to a first payload consisting of N bits (M>N), byrespectively mapping the extracted second payload M-bit value to asingle N-bit value; constructing a first frame according to the secondprotocol that includes the first N-bit payload; and using or sending theconstructed first frame. Any method herein may be used with a memoryhaving M address lines or bits input and N data lines or bits output.Any mapping herein may comprise applying or writing the M-bit payloadvalue as address and reading the N-bit value as output data. Any mappingherein may comprise identifying M−N bit locations, and may furthercomprise compacting by shifting a first register storing the secondM-bit payload so that the identified bit locations are removed.

Any protocol herein, such as the first protocol or the second protocol,may use, may be according to, or may comprise, a vehicle bus protocol.Any data link layer or any physical layer signaling herein of anyvehicle bus protocol herein may be according to, may be based on, mayuse, or may be compatible with, ISO 11898-1:2015 or standard. Anyvehicle bus herein may use, or may be compatible with, a multi-master,serial protocol using acknowledgement, arbitration, and error-detectionschemes, and any vehicle bus herein may consist of, may employ, may use,may be based on, or may be compatible with, a Controller Area Network(CAN). Any CAN herein may be according to, may be based on, may use, ormay be compatible with, a standard selected from the group consisting ofISO 11898-3:2006, ISO 11898-2:2004, ISO 11898-5:2007, ISO 11898-6:2013,ISO 11992-1:2003, ISO 11783-2:2012, SAE J1939/11_201209, SAEJ1939/15_201508, On-Board Diagnostics (OBD), or SAE J2411_200002.Further, Any CAN herein may be according to, may be based on, may use,or may be compatible with, Flexible Data-Rate (CAN FD) protocol.Alternatively or in addition, any vehicle bus herein may consist of, mayemploy, may use, may be based on, or may be compatible with, a LocalInterconnect Network (LIN) standard, that may be according to, may bebased on, may use, or may be compatible with, a standard selected from agroup consisting of ISO 9141-2:1994, ISO 9141:1989, ISO 17987-1, ISO17987-2, ISO 17987-3, ISO 17987-4, ISO 17987-5, ISO 17987-6, and ISO17987-7. Alternatively or in addition, any vehicle bus herein mayconsist of, may employ, may use, may be based on, or may be compatiblewith, FlexRay protocol standard, that may be according to, may be basedon, may use, or may be compatible with, ISO 17458-1:2013, ISO17458-2:2013, ISO 17458-3:2013, ISO 17458-4:2013, or ISO 17458-5:2013.Alternatively or in addition, any vehicle bus herein may consist of, mayemploy, may use, may be based on, or may be compatible with, MediaOriented Systems Transport (MOST) protocol, that may be according to,may be based on, may use, or may be compatible with, MOST25, MOST50, andMOST150. Alternatively or in addition, any vehicle bus herein mayconsist of, may employ, may use, may be based on, or may be compatiblewith, automotive Ethernet that may use a single twisted pair, and may beaccording to, may be based on, may use, or may be compatible with,IEEE802.3 100BaseT1, IEEE802.3 1000BaseT1, BroadR-Reach®, or IEEE802.3bw-2015 standard. Alternatively or in addition, any vehicle busherein may consist of, may employ, may use, may be based on, or may becompatible with, an avionics data bus standard, that may be accordingto, may be based on, may use, or may be compatible with, Aircraft DataNetwork (ADN), Avionics Full-Duplex Switched Ethernet (AFDX),Aeronautical Radio INC. (ARINC) 664, ARINC 629, ARINC 708, ARINC 717,ARINC 825, MIL-STD-1553B, MIL-STD-1760, or Time-Triggered Protocol(TTP).

Any network herein may be a wired network where the transmission mediumcomprises, consists of, or may be part of, two or more conductors, whichmay comprise, may consist of, or may be part of, a stripline, amicrostrip, two wires, or a cable. Any receiving herein may comprisereceiving from a first physical medium, such as from any wired network,and any sending herein may comprise sending to a second physical medium,such as to any wired network. The first physical medium may be differentfrom, identical to, or the same as, the second physical medium.

Any medium herein, such as the first or second medium, may comprise, mayconsist of, or may be part of, a twisted wire pair that comprises, orconsists of, two individually insulated solid or stranded conductors orwires, and the twisted wire pair may comprise, or may consist of, anUnshielded Twisted Pair (UTP) or a Shielded Twisted Pair (STP). Anytwisted wire pair herein may be according to, may be based on, may becompatible with, or may use, ISO/IEC 11801:2002 orANSI/TIA/EIA-568-B.2-2001 standard, and any STP herein be according to,may be based on, may be compatible with, or may use, F/UTP, S/UTP, orSF/UTP. Further, any twisted wire pair herein may be according to, maybe part of, may be based on, may be compatible with, or may use,Category 3, Category 5, Category 5e, Category 6, Category 6A, Category7, Category 7A, Category 8.1, or Category 8.2 cable. Alternatively or inaddition, any wired network herein may comprise, may consist of, or maybe part of, a coaxial cable, and the coaxial cable may comprise adielectric materials are commonly used are foamed polyethylene (FPE),solid polyethylene (PE), polyethylene foam (PF), polytetrafluoroethylene(PTFE), or air space polyethylene (ASP).

Any wired network topology herein may be a point-to-point, bus, star,ring or circular, mesh, tree, hybrid, or daisy chain topology.Alternatively or in addition, the wired network topology may be apoint-to-point topology between two nodes connected to the medium ends,and the communication may be unidirectional, half-duplex, orfull-duplex. The connecting to the medium may comprise connecting to oneof the ends of the medium, or connecting at a point that may be distinctfrom an end of the medium. The medium may comprise, or may consist of,an unbalanced line, signals carried over the medium may employsingle-ended signaling, and the signals may use single-ended signalingthat may be based on, may be according to, or may be compatible with,RS-232 or RS-423 standards. Alternatively or in addition, the medium maycomprise, or may consist of, a balanced line, and signals may be carriedover the medium may employ differential signaling, that may be based on,may be according to, or may be compatible with, RS-232 or RS-423standards. Further, the communication over the medium may use serial orparallel transmission. Any method herein may further comprisetransmitting and receiving digital data over the wired network by awired transceiver coupled to the connector.

Any network herein may be frame or packet based. The topology of anywired network herein may be based on, or may use, point-to-point, bus,star, ring or circular, mesh, tree, hybrid, or daisy chain topology. Anytwo nodes may be connected in a point-to-point topology, and anycommunication herein between two nodes may be unidirectional,half-duplex, or full-duplex. Any medium herein may comprise, or mayconsist of, an unbalanced line, and any signals herein may be carriedover the medium employing single-ended signaling, that may be based on,may be according to, or may be compatible with, RS-232 or RS-423standards. Alternatively or in addition, any medium herein maycomprises, or may consist of, a balanced line, and any signals hereinmay be carried over the medium employing differential signaling, thatmay be based on, may be according to, or may be compatible with, RS-232or RS-423 standards. Any communication over a medium herein may useserial or parallel transmission.

Any network herein may be a Personal Area Network (PAN), any connectorherein may be a PAN connector, and any transceiver herein may be a PANtransceiver. Alternatively or in addition, any network herein may be aLocal Area Network (LAN) that may be Ethernet-based, ant connectorherein may be a LAN connector, and any transceiver herein may be a LANtransceiver. The LAN may be according to, may be compatible with, or maybe based on, IEEE 802.3-2008 standard. Alternatively or in addition, theLAN may be according to, may be compatible with, or may be based on,10Base-T, 100Base-T, 100Base-TX, 100Base-T2, 100Base-T4, 1000Base-T,1000Base-TX, 10GBase-CX4, or 10 GBase-T; and the LAN connector may be anRJ-45 type connector. Alternatively or in addition, the LAN may beaccording to, may be compatible with, or may be based on, 10Base-FX,100Base-SX, 100Base-BX, 100Base-LX10, 1000Base-CX, 1000Base-SX,1000Base-LX, 1000Base-LX10, 1000Base-ZX, 1000Base-BX10, 10GBase-SR,10GBase-LR, 10GBase-LRM, 10GBase-ER, 10GBase-ZR, or 10GBase-LX4, and theLAN connector may be a fiber-optic connector. Alternatively or inaddition, any network herein may be a packet-based or switched-basedWide Area Network (WAN), any connector herein may be a WAN connector,and any transceiver herein may be a WAN transceiver. Alternatively or inaddition, any network herein may be according to, may be compatiblewith, or may be based on, a Serial Peripheral Interface (SPI) bus,Inter-Integrated Circuit (I²C) bus, or 1-Wire bus.

Any method herein may be used for lossless or for stateless compressingof a first M-bit set to a second M-S bit set, and any method herein maybe used multiple M-bit sets that may include the first M-bit set.Further, any method herein may comprise calculating correlationinformation between two or more M-bit locations in the multiple M-bitsets; obtaining the first M-bit set at a first device; forming, in thefirst device, the second M-S bit set using the correlation information;sending, by the first device, the second M-S bit set to a second device;receiving, by the second device, the second M-S bit set; andconstructing the first M-bit set from the received second M-S bit setusing the correlation information. Any method herein may compriseminimizing the multiple M-bit sets by removing a set that is identicalto another set of the multiple sets.

Any method herein may be used with a first protocol that may defineframes that may include a fixed length payload consisting of M bits. Thefirst M-bit set and each of the multiple M-bit sets may be a payload ina frame according to the first protocol. The obtaining of the firstM-bit set at a first device may comprise receiving, by the first device,a frame that comprises as a payload the first M-bit set, or may compriseextracting, by the first device, the first M-bit set from the receivedframe. Alternatively or in addition, the obtaining of the first M-bitset at a first device may comprise may comprise generating of themultiple M-bit sets according to, or based on, the first protocol.Alternatively or in addition, any method herein may comprise receivingof the multiple M-bit sets, and the receiving may comprise receivingfrom a communication medium multiple frames that include the multipleM-bit sets as payloads, and may further comprise extracting the multipleM-bit sets from the received frames.

The number of the sets in any multiple M-bit sets herein may be equalto, less than, or higher than, 3, 4, 5, 7, 10, 15, 20, 30, 50, 100, 200,500, 1,000, 2,000, 5,000, 10,000, 20,000, 50,000, 100,000, 200,000,500,000, or 1,000,000. Alternatively or in addition, the number of thesets in any multiple M-bit sets herein may be equal to, or less than,0.1%, 0.2%, 0.5%, 1%, 2%, 3%, 5%, 10%, 15%, 20%, 30%, or 50% of 2^(M).Further, the number of the sets in any multiple M-bit sets herein may beequal to, or less than, 2^(M-S).

Any method herein may be used with a first protocol that may defineframes that may include a fixed length payload that may be consisting ofM bits. Any first M-bit set herein and each of any multiple M-bit setsherein may be a payload in a frame according to the first protocol. Anyfirst protocol herein may be according to, may be based on, may use, ormay be compatible with, a vehicle bus protocol. Any data link layer or aphysical layer signaling herein of any vehicle bus protocol herein maybe according to, may be based on, may uses, or may be compatible with,ISO 11898-1:2015 or standard. Any vehicle bus herein may use, or may becompatible with, a multi-master, serial protocol using acknowledgement,arbitration, and error-detection schemes, such as any vehicle bus thatmay consist of, may employ, may use, may be based on, or may becompatible with, a Controller Area Network (CAN) protocol, and Any CANherein may be is according to, may be based on, may use, or may becompatible with, a standard that may be selected from the groupconsisting of ISO 11898-3:2006, ISO 11898-2:2004, ISO 11898-5:2007, ISO11898-6:2013, ISO 11992-1:2003, ISO 11783-2:2012, SAE J1939/11_201209,SAE J1939/15_201508, On-Board Diagnostics (OBD), and SAE J2411_200002.

Further, any CAN herein may be according to, may be based on, may use,or may be compatible with, Flexible Data-Rate (CAN FD) protocol.Alternatively or in addition, any vehicle bus herein may be accordingto, may be based on, may use, or may be compatible with, a LocalInterconnect Network (LIN) standard that may be according to, may bebased on, may use, or may be compatible with, a standard selected from agroup consisting of ISO 9141-2:1994, ISO 9141:1989, ISO 17987-1, ISO17987-2, ISO 17987-3, ISO 17987-4, ISO 17987-5, ISO 17987-6, and ISO17987-7. Alternatively or in addition, any vehicle bus herein may beaccording to, may be based on, may use, or may be compatible with,FlexRay protocol standard that may be according to, may be based on, mayuse, or may be compatible with, a standard selected from a groupconsisting of ISO 17458-1:2013, ISO 17458-2:2013, ISO 17458-3:2013, ISO17458-4:2013, or ISO 17458-5:2013. Alternatively or in addition, anyvehicle bus herein may be according to, may be based on, may use, or maybe compatible with, Media Oriented Systems Transport (MOST) protocol,that may be according to, may be based on, may use, or may be compatiblewith, a standard selected from a group consisting of MOST25, MOST50, andMOST150.

Alternatively or in addition, any vehicle bus herein may be accordingto, may be based on, may use, or may be compatible with, automotiveEthernet that may use a single twisted pair and may be according to, maybe based on, may use, or may be compatible with, IEEE802.3 100BaseT1,IEEE802.3 1000BaseT1, BroadR-Reach®, or IEEE 802.3bw-2015 standard.Alternatively or in addition, any vehicle bus herein may be accordingto, may be based on, may use, or may be compatible with, avionics databus standard may be according to, may be based on, may use, or may becompatible with, Aircraft Data Network (ADN), Avionics Full-DuplexSwitched Ethernet (AFDX), Aeronautical Radio INC. (ARINC) 664, ARINC629, ARINC 708, ARINC 717, ARINC 825, MIL-STD-1553B, MIL-STD-1760, orTime-Triggered Protocol (TTP).

Any ratio M/(M-S) value herein may be equal to, or may be more than,1.1, 1.2, 1.5, 2, 2.5, 3, 3.5, 5, 7, 10, 15, 20, 30, 50, or 100.Alternatively or in addition, the ratio M/(M-S) value herein may be lessthan 1.2, 1.5, 2, 2.5, 3, 3.5, 5, 7, 10, 15, 20, 30, 50, or 100.Alternatively or in addition, the ratio 2^(M)/2^(M-S)=2^(S) value may beequal to, or may be more than, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024,or 2048, or may be less than 4, 8, 16, 32, 64, 128, 256, 512, 1024, or2048. Any M-S value herein may be equal to, or may be more than, 4, 8,12, 16, 32, 64, 128, 256, 512, or 1024. Alternatively or in addition,any M-S value herein may be less than 8, 12, 16, 32, 64, 128, 256, 512,or 1024. Any M value herein may be equal to, or may be more than, 4, 8,12, 16, 32, 64, 128, 256, 512, or 1024. Alternatively or in addition,any M value herein may be less than 8, 12, 16, 32, 64, 128, 256, 512, or1024.

Any method herein may be used with an M-bit code that may be part of thecorrelation information. Any method may further comprise for each one ofthe M locations checking whether the same value of bits in the locationin all of the multiple M-bit sets carry the same value; marking thelocation in which the same value of bits in the location in all of themultiple M-bit sets carry the same value; responsive to determining thatall bit values in all of the multiple M-bit sets in ‘0’, assigning ‘0’to the respective location in the M-bit code; and responsive todetermining that all bit values in all of the multiple M-bit sets in‘1’, assigning ‘1’ to the respective location in the M-bit code. Anynumber of marked locations herein may be S. Any forming of the secondM-S bit set herein may comprise removing the marked S locations from thefirst M-bit set, and any constructing herein may comprise assigning therespective value in the code to the marked S locations.

Any method herein may be used with an M-bit code that may be part of thecorrelation information. Any method herein may further comprise, foreach pair of first and second distinct locations of the M locations:checking whether the second location carries the same or the complementvalue of bits of the first location in all of the multiple M-bit sets;marking the second location which carries the same or the complementvalue of bits of the first location in all of the multiple M-bit sets;responsive to determining that the second location carries the samevalue of bits of the first location in all of the multiple M-bit sets,assigning ‘0’ and the first location identifier to the respectivelocation in the M-bit code; and responsive to determining that thesecond location carries the complement value of bits of the firstlocation in all of the multiple M-bit sets, assigning ‘1’ and the firstlocation identifier to the respective location in the M-bit code, andany number of marked locations may be S. Any forming of the second M-Sbit set may comprise removing the marked S locations from the firstM-bit set, and any constructing herein may comprise assigning the valueof each of the marked locations to be the same value as the locationidentified by the respective identifier in the M-bit code if ‘0’ isrespectively assigned, and any constructing herein may compriseassigning the value of each of the marked locations to be the complementvalue as the location identified by the respective identifier in theM-bit code if ‘1’ is respectively assigned.

Any method herein may further comprise selecting distinct Q distinctlocations of the M locations, where Q>1 and Q<M; checking whether afirst one of the locations can be represented as a function of the otherQ−1 locations in the multiple M-bit sets; and responsive to determiningthat first one of the locations can be represented as a function of theother Q−1 locations marking the first location and storing the functionas part of the correlation information and the forming of the second M-Sbit set comprises removing the marked first locations from the firstM-bit set. There may be equal to, or less than, 2^(Q-1) different valuesof the distinct Q distinct locations in the multiple M-bit sets, and anyfunction herein may be a Boolean function. Alternatively or in addition,there may be equal to, or less than, 2^(Q-1) different values of thedistinct Q distinct locations in the multiple M-bit sets, and (Q−1) bitsdistinct values may be assigned to each of the 2^(Q-1) different values.Any correlation information herein may comprise the assignment of the(Q−1) bits distinct values to the corresponding 2^(Q-1) differentvalues, and the values in the non-marked locations may be replaced withthe (Q−1) bits distinct values according to the assignment. Any steps ofany method herein may be repeated after the replacing, and may furtherbe repeated for all possible selecting of distinct Q distinct locationsfrom the M locations, where Q>1 and Q<M, or may be repeated for allpossible Q values from Q=2 to Q=M−1.

Any device herein may be used for a lossless and statelessde-compression scheme, and may further be used with a group of multipleframes that are according to a first protocol and includes, in a fixedlocation in the frames, a fixed length payload consisting of M bits. Thenumber of values in the first payload may be equal to, or may be lessthan, 2^(N) possible values. Any device herein may comprise a connectorfor connecting to a vehicle bus; a receiver coupled to the connector forreceiving from the vehicle bus a plurality of frames according to asecond protocol that include a fixed length payload consisting of Nbits; a software and a processor for executing the software; a memorycoupled to the processor for storing a set of rules; a transmittercoupled to the processor for sending a second frame according to thefirst protocol to another device; and a single enclosure housing theconnector, the receiver, the processor, the memory, and the transmitter.Any processor herein may be operative in real-time, for each of areceived first frame out of the plurality of frames, to identify andextract a first N-bit payload from the received first frame, to map thefirst payload to a second payload consisting of M bits (M>N), byrespectively associating a single M-bit value to the extracted firstpayload N-bit value, and to construct the second frame that includes thesecond M-bit payload and is part of the group.

A non-transitory computer readable medium may include computerexecutable instructions stored thereon, wherein the instructions mayinclude any step or steps, any method, or any flow chart describedherein. Any method or apparatus herein may perform any step or steps,any method, or any flow chart described herein.

The above summary is not an exhaustive list of all aspects of thepresent invention. Indeed, the inventor contemplates that his inventionincludes all systems and methods that can be practiced from all suitablecombinations and derivatives of the various aspects summarized above, aswell as those disclosed in the detailed description below, andparticularly pointed out in the claims filed with the application. Suchcombinations have particular advantages not specifically recited in theabove summary.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is herein described, by way of non-limiting examples only,with reference to the accompanying drawings, wherein like designationsdenote like elements. Understanding that these drawings only provideinformation concerning typical embodiments of the invention and are nottherefore to be considered limiting in scope:

FIG. 1 illustrates schematically a data frame format;

FIG. 2 illustrates schematically a data frame format as defined by aController Area Network (CAN) protocol;

FIG. 3 illustrates a table of the various classification levels ofautonomous car is according to the Society of Automotive Engineers (SAE)J3016 standard;

FIG. 4 illustrates schematically a block diagram of a balancedmulti-point (bus) wired network;

FIG. 5 illustrates schematically a block diagram of an automotive bususing a Controller Area Network (CAN) connecting multiple ECUs;

FIG. 6 illustrates schematically general reconstructing a frame from areceived compressed frame;

FIG. 6a illustrates schematically general reconstructing a frame from areceived compressed frame using a memory or PLD;

FIG. 6b illustrates schematically general reconstructing a frame from areceived compressed frame using a processor;

FIG. 7 illustrates schematically general reconstructing a frame from areceived compressed frame using a combinatorial logic;

FIG. 7a illustrates schematically general reconstructing a frame from areceived compressed frame using a combinatorial logic based on storedcoefficients;

FIG. 8 illustrates schematically a simplified flowchart ofreconstructing an original frame from a received compressed frame;

FIG. 9 illustrates schematically general reconstructing three framesfrom a received single compressed frame;

FIG. 10 illustrates schematically general reconstructing a frame from areceived compressed frame that includes an added code field;

FIG. 10a illustrates schematically general reconstructing an unchangedframe from a received compressed frame having an indicator;

FIG. 10b illustrates schematically general reconstructing a frame from areceived compressed frame and setting a hit according to an indicator;

FIG. 11 illustrates schematically general compressing of a frame from areceived uncompressed frame;

FIG. 11a illustrates schematically general compressing of a frame from areceived uncompressed frame using a memory or PLD;

FIG. 11b illustrates schematically general compressing of a frame from areceived uncompressed frame using a processor;

FIG. 11c illustrates schematically general uncompressing of a frame froma received uncompressed frame and generating an indicator;

FIG. 11d illustrates schematically general compressing of a frame from areceived uncompressed frame except a bit associated with an indicator;

FIG. 12 depicts a data histogram of values transmitted over a CAN busbefore compression;

FIG. 12a depicts a data histogram of values transmitted over a CAN busafter compression;

FIG. 13 illustrates schematically a simplified flowchart of compressingan original frame into a compressed frame;

FIG. 14 illustrates schematically a simplified flowchart of forming of acompression scheme from obtained samples;

FIG. 14-1 illustrates schematically a simplified flowchart of forming ofa compression scheme from obtained samples using samples modifying;

FIG. 14a illustrates schematically a simplified flowchart of forming ofa compression scheme using a single location;

FIG. 14b illustrates schematically a simplified flowchart of forming ofa compression scheme using two locations;

FIG. 14c illustrates schematically a simplified flowchart of forming ofa compression scheme using three locations;

FIG. 14d illustrates schematically a simplified flowchart of forming ofa compression scheme using Q locations;

FIG. 15 illustrates schematically an example of a table of obtainedsamples before any compression stage;

FIG. 15a illustrates schematically an example of a table of obtainedsamples after first stage of a single location compression;

FIG. 15b illustrates schematically an example of a table of obtainedsamples after first stage of two locations compression;

FIG. 15c illustrates schematically an example of a table of obtainedsamples after first stage of three locations compression without samplesmodifying;

FIG. 15d illustrates schematically an example of a table of obtainedsamples after first stage of three locations compression using samplesmodifying;

FIG. 16 illustrates schematically an example of developing compressioncode after various stages of compression;

FIG. 16a illustrates schematically another example of developingcompression code after various stages of compression;

FIG. 17 depicts pictorially compressing a word having M locations into a4 bits word; and

FIG. 17a depicts pictorially uncompressing a 4 bits word into a wordhaving M locations.

DETAILED DESCRIPTION

The principles and operation of an apparatus according to the presentinvention may be understood with reference to the figures and theaccompanying description wherein similar components appearing indifferent figures are denoted by identical reference numerals. Thedrawings and descriptions are conceptual only. In actual practice, asingle component can implement one or more functions; alternatively orin addition, each function can be implemented by a plurality ofcomponents and devices. In the figures and descriptions, identicalreference numerals indicate those components that are common todifferent embodiments or configurations. Identical numerical references(even in the case of using different suffix, such as 5, 5a, 5b and 5c)refer to functions or actual devices that are either identical,substantially similar, or having similar functionality. It will bereadily understood that the components of the present invention, asgenerally described and illustrated in the figures herein, could bearranged and designed in a wide variety of different configurations.Thus, the following more detailed description of the embodiments of theapparatus, system, and method of the present invention, as representedin the figures herein, is not intended to limit the scope of theinvention, as claimed, but is merely representative of embodiments ofthe invention. It is to be understood that the singular forms “a,” “an,”and “the” herein include plural referents unless the context clearlydictates otherwise. Thus, for example, a reference to “a componentsurface” includes reference to one or more of such surfaces. The term“substantially” means that the recited characteristic, parameter, orvalue need not be achieved exactly, but that deviations or variations,including for example, tolerances, measurement error, measurementaccuracy limitations, and other factors known to those of skill in theart, may occur in amounts that do not preclude the effect thecharacteristic was intended to provide.

The transfer of digital data signals between two devices, systems, orcomponents, commonly makes use of a line driver for transmitting thesignal to the conductors serving as the transmission medium connectingthe two modules, and a line receiver for receiving the transmittedsignal from the transmission medium. The communication may use aproprietary interface or preferably an industry standard, whichtypically defines the electrical signal characteristics such as voltagelevel, signaling rate, timing and slew rate of signals, voltagewithstanding levels, short-circuit behavior, and maximum loadcapacitance. Further, the industry standard may define the interfacemechanical characteristics such as the pluggable connectors, and pinidentification and pin-out. In one example, the module circuit can usean industry or other standard used for interfacing serial binary datasignals. Preferably the line drivers and line receivers and theirassociated circuitry will be protected against electrostatic discharge(ESD), electromagnetic interference (EMI/EMC), and against faults(fault-protected), and employs proper termination, failsafe scheme andsupports live insertion. Preferably, a point-to-point connection schemeis used, wherein a single line driver is communicating with a singleline receiver. However, multi-drop or multi-point configurations may aswell be used. Further, the line driver and the line receiver may beintegrated into a single IC (Integrated Circuit), commonly known astransceiver IC.

A line driver typically converts the logic levels used by the moduleinternal digital logic circuits (e.g., CMOS, TTL, LSTTL and HCMOS) to asignal to be transmitted. In order to improve the common-mode noiserejection capability, and to allow higher data rates, a balanced anddifferential interface may be used. For example, a balanced interfaceline driver may be an RS-422 driver such as RS-422 transmitter MAX3030E,available from Maxim Integrated Products, Inc. of Sunnyvale, Calif.,U.S.A., described in the data sheet “±15 kV ESD-Protected, 3.3V QuadRS-422 Transmitters” publication number 19-2671 Rev.0 10/02, which isincorporated in its entirety for all purposes as if fully set forthherein. A line receiver typically converts the received signal to thelogic levels used by the module internal digital logic circuits (e.g.,CMOS, TTL, LSTTL and HCMOS). For example, industry standard TIA/EIA-422(a.k.a. RS-422) can be used for a connection, and the line receiver maybe an RS-422 compliant line receiver, such as RS-422 receiver MAX3095,available from Maxim Integrated Products, Inc. of Sunnyvale, Calif.,U.S.A., described in the data sheet “±15 kV ESD-Protected, 10 Mbps,3V/5V, Quad RS-422/RS-485 Receivers” publication number 19-0498 Rev.110/00, which is incorporated in its entirety for all purposes as iffully set forth herein. American national standard ANSI/TIA/EIA-422-B(formerly RS-422) and its international equivalent ITU-T RecommendationV.11 (also known as X.27), are technical standards that specify the“electrical characteristics of the balanced voltage digital interfacecircuit”. These technical standards provide for data transmission, usingbalanced or differential signaling, with unidirectional/non-reversible,terminated or non-terminated transmission lines, point to point.Overview of the RS-422 standard can be found in National SemiconductorApplication Note 1031 publication AN012598 dated January 2000 andtitled: “TIA/EIA-422-B Overview” and in B&B Electronics publication“RS-422 and RS-485 Application Note” dated June 2006, which areincorporated in their entirety for all purposes as if fully set forthherein.

A transmission scheme may be based on the serial binary digital datastandard Electronic Industries Association (EIA) and TelecommunicationsIndustry Association (TIA) EIA/TIA-232, also known as RecommendedStandard RS-232 and ITU-T (The Telecommunication Standardization Sector(ITU-T) of the International Telecommunication Union (ITU)) V.24(formerly known as CCITT Standard V.24). Similarly, RS-423 based serialsignaling standard may be used. For example, RS-232 transceiver MAX202Emay be used, available from Maxim Integrated Products, Inc. ofSunnyvale, Calif., U.S.A., described in the data sheet “±12 kVESD-Protected, +5V RS-232 Transceivers” publication number 19-0175 Rev.63/05, which is incorporated in its entirety for all purposes as if fullyset forth herein.

A 2-way communication interface may use the EIA/TIA-485 (formerlyRS-485), which supports balanced signaling and multipoint/multi-dropwiring configurations. Overview of the RS-422 standard can be found inNational Semiconductor Application Note 1057 publication AN012882 datedOctober 1996 and titled: “Ten ways to Bulletproof RS-485 Interfaces”,which is incorporated in their entirety for all purposes as if fully setforth herein. In this case, RS-485 supporting line receivers and linedriver are used, such as for example, RS-485 transceiver MAX3080 may beused, available from Maxim Integrated Products, Inc. of Sunnyvale,Calif., U.S.A., described in the data sheet “Fail-Safe, High-Speed (10Mbps), Slew-Rate-Limited RS-485/RS-422 Transceivers” publication number19-1138 Rev.3 12/05, which is incorporated in its entirety for allpurposes as if fully set forth herein.

The payload 12 of the frame 10 includes M bits (or locations), hence mayrepresent theoretical 2^(M) different values. However, practically thecarried values are not random and not all the permutations are actuallyused. For example, the field ‘A’ 14 a includes 4 locations or bits,hence may carry 16 values, ranging from 0 to 15. However, a protocol maydefine only few of these values (such as only 0 to 12), and few valuesmay be reserved or used only for special purposes. Similarly, indicationbits, such as indicator bit 15, may be of fixed value according to astandard for alignment or synchronization purposes. In another example,a field of 8 bits may be used to carry a value of a magnitude rangingfrom 0 to 255, such as a sensor output value. However, in actualimplementation only the values from 56 to 178 are actually used.Furthermore, there may inter-dependency between two or more field in theframe 10, so that not all possible values are actually used for thefield combinations.

Further, a protocol may be designed to various applications, and thusincludes options for many possible values. However, when used in aspecific application, some of the possible values in the fields may notbe practically used. For example, the CAN protocol is used for bothautomotive and industrial applications. When used in a specificautomotive application, not all the possible options of the fields maybe actually used. Furthermore, a specific vehicle manufacturer, or in aspecific vehicle model by a manufacturer, may only use part of theprotocol options. In addition, a specific installation, such as in aspecific car by a specific owner, may further use a more limited set ofthe possible variants offered by the standard. In an example of anambient temperature sensor, a vehicle used in a ‘cold’ state, such as inAlaska, may use only a lower part of the temperature range, while whenthe same vehicle is used in a ‘hot’ state such as California, may useonly a higher part of the same temperature range.

Since not all of the theoretical 2^(M) different values may be actuallyused, a compression scheme may be used, where the M bits of the payload12 are represented by N bits (or locations), and wherein N<M. Forexample, it may be beneficial to compress (by coding or bydictionary-based compression) 64-bit long numbers (data blocks) from acertain set (such as payload carried over a CAN bus) to a shorter dataformat. For example, if a set size s is less than 264 elements, ans-long dictionary may be compiled, which will contain all uniqueelements of the set. The maximal length of such ‘compressed’ length willbe log 2(s) bits. In one example, only 64·s bits of memory to hold thewhole dictionary may be required. Such compression may preferably belossless (inversible compression), and may preferably be stateless—suchas on the basis of a frame-by-frame basis (and not depending upon anyformer received frame or frames), and may be based on the locations ofdata or bits in the frame structure. The compression may be based onthat there are some general patterns and correlations between bits indifferent positions in frames in a specific application or installationthat may results in a payload data that includes some regularities andis not entirely random.

A schematic arrangement or method 65 of reconstructing by usingde-compression of the frame 10 from a received compressed frame 60 isshown in FIG. 6. The frame 60 is defined as starting with a header 61,including few bits, and ends with a trailer (also known as ‘footer’) 63bits. The data carried by the frame 60 is referred to as payload 62, andis positioned between the header 61 and the trailer 63. In the exampleof the frame 60, the payload 62 comprises a most LSB bit (or position)b₀ 62 a, which is followed by bit or location b₁ 62 b, and then followedby bits (or locations) b₂ 62 c and b ₃ 62 d. The payload 62 ends withbits b_(N-3) 62 f, followed by bit or location b_(N-2) 62 g, and endingwith the MSB bit or location b_(N-1) 62 h, totaling of N bits in thepayload 62. While frame 60 is shown where the LSB bits (or locations)follow the header 61 and the MSB bits (or locations) precede the trailer63, frames can equally use a reverse order, where MSB bits (orlocations) that follow the header 61 and LSB bits (or locations) thatprecede the trailer 63. It is assumed that the number of combination ofvalues in the payload 12 of the frame 10 is equal to, or less than,2^(N), so a compression is obtained since N<M.

The N bits forming the payload 62 of the frame 60 are orderly extractedfrom the frame 60, and are fed as input 66 a, via a bus, a physicalconnection, or as software or firmware variable, to a mapping block orfunctionality 67. For each value of the input 66 a, the mappingfunctionality 67 assign a set of M bits, which are fed via output 66 bto form the payload 12 of the original frame 10 (before beingcompressed).

The mapping functionality 67 may be implemented using a memory 67 a asshown in an arrangement 65 a shown in FIG. 6a , where the memory 67 aserves as a Look-Up Table (LUT). In such a configuration, the input Nbits 66 a are used as an input providing an address to the memory 67 a,and the data stored at the input address is the M bits output 66 b.

In one example, the compression is stateless. Hence not dependent uponany former data, but rather may be represented as a combinatorial logicapplied to the input N bits 66 a, to produce the M bits output 66 b.Such combinatorial logic may be implemented using logic gates thatperform a logical operation on one or more binary inputs and producesbinary outputs.

Logic gates are primarily implemented using diodes or transistors actingas electronic switches. With amplification, logic gates can be cascadedin the same way that Boolean functions can be composed, allowing theconstruction of a physical model of all of Boolean logic, and therefore,all of the algorithms and mathematics that can be described with Booleanlogic. Logic circuits include such devices as multiplexers, registers,Arithmetic Logic Units (ALUs), and computer memory. In modern practice,most gates are made from field-effect transistors (FETs), particularlymetal-oxide-semiconductor field-effect transistors (MOSFETs). Compoundlogic gates AND-OR-Invert (AOI) and OR-AND-Invert (OAI) are oftenemployed in circuit design because their construction using MOSFETs issimpler and more efficient than the sum of the individual gates.

Hence, alternatively or in addition to using a memory, a PLD 67 a may beused for obtaining the required M bits output 66 b as a function of theN bits input 66 a. For example, the lookup table functionality may beimplemented with a multiplexer whose select lines are driven by theaddress signal and whose inputs are the values of the elements containedin the array. These values can either be hard-wired, as in an ASIC whichpurpose is specific to a function, or provided by D latches which allowfor configurable values. An n-bit LUT can encode any n-input Booleanfunction by storing the truth table of the function in the LUT. This isan efficient way of encoding Boolean logic functions.

In the example shown in the arrangement 65 a, a hardware onlyimplementation may be used to implement the mapping functionality 67,such as a memory or PLD 67 a. Alternatively or in addition, a mappingfunctionality 67 b may be based on a processor 64 and a memory 69 asshown in an arrangement 65 b in FIG. 6b . The received N bits on input66 a are stored in a temporary input memory 68 a, which may be aregister, a shift register, a buffer, or any other memory suitable tostore the received N bits. The memory 69 includes firmware or softwarefor operating the processor 64, and further store the transfer functionrelating the compression, so that the processor 64 may apply thede-compression information stored in the memory 69 to the data in theregister 68 a, and provide an output M bits to an output register 68 b(or other temporary memory), to be fed to the output 66 b. For example,the processor 64 may calculate a bit at a time and sequentially writethe calculated bits to the register 68 b.

An example of using logic gates to implement a combinatorial function 72to form the mapping functionality 67 is described in an arrangement 70shown in FIG. 7. In one example, one or more bits, such as indicatorbits, may be assigned a fixed value, such as ‘0’ or ‘1’. In such a case,the mapping functionality 72 output the fixed value to the relevantlocation. For example, the location a₂ 12 c is shown as being alwaysassign a value of ‘1’ via an output 71 e. Further, one or more bits maybe assigned a value depending on only a single input bit. For example,the location a₀ 12 a is shown as being affected only by the input b₂ 62c. In such a case, a logic circuit 71 a having a single input and asingle output is used, which may transfer the actual value of the inputbit or its inverse value. Similarly, one or more bits may be assigned avalue depending on two input bits. For example, the location a₄ 12 e isshown as being affected only by the two inputs b₁ 62 b and b _(N-3) 62f. In such a case, a logic circuit 71 b having two inputs and a singleoutput is used, which may perform any Boolean action on the two inputs,such as ‘AND’, ‘OR’, ‘NAND’, ‘NOR’, ‘XOR’, or ‘NXOR’. Similarly, one ormore bits may be assigned a value depending on three input bits. Forexample, the location a_(M-2) 12 g is shown as being affected only bythe three inputs b₂ 62 c, b_(N-3) 62 f, and b _(N-1) 62 h. In such acase, a logic circuit 71 c having three inputs and a single output isused, which may perform any Boolean action on the three inputs.Similarly, one or more bits may be assigned a value depending on all Ninput bits. In such a case, a logic circuit 71 d having N inputs and asingle output is used, which may perform any Boolean action on the Ninputs as required.

While in the example of the arrangement 70 shown in FIG. 7 a singlelocation or bit a₂ 12 c is assigned a fixed ‘1’ value 71 e regardless ofany other bit or location in the payload 62, any number of bits orlocations may equally be set to a fixed value of ‘1’ or ‘0’, regardlessof any other bit or location in the payload 62. For example, the numberof bits or locations from the M bits or locations of the payload 12 thatmay be assigned as ‘0’ or ‘1’ for any compressed payload 62 may be equalto, less than, or more than, 2, 3, 4, 5, 7, 10, 15, 20, 30, 50, 70, or100. Alternatively or in addition, the number of bits or locations fromthe M bits or locations of the payload 12 that may be assigned as ‘0’ or‘1’ for any compressed payload 62 may be equal to, less than, or morethan, 1%, 2%, 3%, 5%, 7%, 10%, 15%, 20%, 25%, 30%, 50%, 60%, or 70% ofthe M bits or locations.

In a general case, each output may be represented and mapped by a mapper72 a (that acts as a decoder or a de-compressor) as being dependent ofall N input bits using a set of N+1 coefficients, as illustrated in anarrangement 70 a shown in FIG. 7a . The set of N+1 coefficients (foreach output bit) is stored in a coefficients memory 73, and is used bythe logic block or functionality 71 f. In the example of the arrangement70 a, only a single output bit a₃ 12 d is illustrated for simplicitysake, while practically a set of N+1 coefficients is stored and used foreach one of the M output bits, requiring the coefficients memory 73 tostore M*(N+1) coefficients.

Any polynomial coefficients (referring to each term between twosummations has more than one b_(i)) scheme may be used. In one example,while calculating the output bit a₃ 12 d by the logic block 71 f that isshown in the arrangement 70 a in FIG. 7a , the one-bit coefficients setmay be designated as (c, c₀, c₁, . . . , c_(N-1), c_(0, 1), c_(0, 2), .. . , c_(N-2, N-1), c_(0, 1, 2), . . . , c_(0, 1, . . . , N-2), . . . ,c_(1, 2, . . . , N-2, N-1)), where the subset (c₀, c₁, . . . , c_(N-1),c_(0, 1), c_(0, 2), . . . , c_(N-2, N-1), c_(0, 1, 2), . . . ,c_(0, 1, . . . , N-2), . . . , c_(1, 2, . . . , N-2, N-1)) correspondsto the N input bits (b₀, b₁, b₂, b₃, . . . b_(N-3), b_(N-2), b_(N-1))and c is an additional and independent coefficient. The calculation bythe logic block 71 f may be according to:a ₃ =c⊕c ₀ ·b ₀ ⊕c ₁ ·b ₁ ⊕ . . . ⊕c _(N-1) ·b _(N-1)⊕c _(0,1) ·b ₀ ·b ₁ ⊕c _(0,2) ·b ₀ ·b ₂ ⊕ . . . c _(N-2,N-1) ·b _(N-2) ·b_(N-1)⊕. . .c _(0,1, . . . ,N-2) ·b ₀ ·b ₁ · . . . ·b _(N-2) ⊕ . . . ⊕c_(1,2, . . . ,N-2,N-1) ·b ₁ · . . . ·b _(N-2) ·b _(N-1),where the summation ‘⊕’ is the modulo-2 summation.

Any polynomial coefficients scheme may be used. In one example, whilecalculating the output bit a₃ 12 d by the logic block 71 f that is shownin the arrangement 70 a in FIG. 7a , the coefficients set may bedesignated as (c₀, c₁, c₂, c₃, . . . c_(N-3), c_(N-2), c_(N-1), c_(N)),where the subset (c₀, c₁, c₂, c₃, . . . c_(N-3), c_(N-2), c_(N-1))corresponds to the N input bits (b₀, b₁, b₂, b₃, . . . b_(N-3), b_(N-2),b_(N-1)) and c_(N) is an additional and independent coefficient. Thecalculation by the logic block 71 f may be according to:a₃=c₀*b₀+c₁*b₁+c₂*b₂+c₃*b₃+ . . .c_(N-3)*b_(N-3)+c_(N-2)*b_(N-2)+c_(N-1)*b_(N-1)+c_(N), where thesummation is modulo-2 summation. Alternatively, the XOR function oroperation (designated as ‘⊕’) may be used, to obtaina₃=c₀⊕b₀+c₁⊕b₁+c₂⊕b₂+c₃⊕b₃+ . . .c_(N-3)⊕b_(N-3)+c_(N-2)⊕b_(N-2)+c_(N-1) ⊕b_(N-1)+c_(N).

An example of a flow chart 80 of reconstructing a frame from acompressed version is shown in FIG. 8. A compressed frame, such as theframe 60 described in FIG. 6, is received as part of a “ReceiveCompressed Frame” step 81. The frame may be received from acommunication medium, using any physical layer (OSI Layer 1) standard orprotocol, such as the medium 16 shown in the arrangement 40 in FIG. 4,and may use a transceiver such as the transceiver 43 a in the device 41a. The received compressed frame is Layer-2 handled, such as by a frameror controller 57 a as part of the device 56 a shown in FIG. 5. Thepayload 62 is identified and extracted as part of an “Extract Payload”step 82. The extracted payload 62 is then mapped into an output thatprovides the original and uncompressed payload 12 as part of a “MapPayload” step 83. The mapped payload 12 is then embedded to reconstructthe original frame 10, using Layer-2 handling, as part of a “ReconstructFrame” step 84, and the reconstructed frame 10 may be used as part of a“Transmit/Use Reconstructed Frame” step 85. For example, thereconstructed frame 10 may be transmitted over a communication mediumusing any physical layer scheme.

The compressed frame 60 received as part of the “Receive CompressedFrame” step 81, may be according to, or based on, a protocol, such asany OSI Layer-2 protocol, that may be the same or different from theprotocol used by the constructed frame 10 as part the “ReconstructFrame” step 84. For example, the same or different frame structure, datarate, fields and indicators locations and definitions may be used. Inthe case wherein different protocols are used, the flow chart 80 may bepart of, or may further include, a protocol conversion scheme. Anyprotocol herein, may consist of, may include, may be based on, or may beaccording to, an Open Systems Interconnection (OSI) Layer-3 or Layer-4standard protocol, that may consist of, may include, may be based on, ormay be according to, ISO 15765-2 standard, such as ISO 15765-2:2004ISO-TP (Transport Layer) standard.

In one example, the ratio M/N may be used as a compression ratio thatmay be used quantify the reduction in the data representation sizeproduced by the compression algorithm or method herein. Such a rationaffectively estimates or measures the data rate reduction of carryingthe data or the payload. For example, the ration M/N may be equal to,more than, or less than, 1.1, 1.2, 1.5, 2, 2.5, 3, 3.5, 5, 7, 10, 15,20, 30, 50, or 100.

Alternatively or in addition, the ratio 2^(M)/2^(N)=2^(M-N) may be usedas a compression ratio that may be used quantify the reduction in thedata representation size produced by the compression algorithm or methodherein. Such a ration affectively estimates or measures the number ofpossible values in the output before compression versus the number ofpossible values after compression. For example, the ration 2^(M-N) maybe equal to, more than, or less than, 2, 4, 8, 16, 32, 64, 128, 256,512, 1024, or 2048.

The number N of bits in the payload 62 may be equal to, more than, orless than, 4, 8, 12, 16, 32, 64, 128, 256, 512, or 1024. Similarly, thenumber M of bits in the payload 12 may be equal to, more than, or lessthan, 4, 8, 12, 16, 32, 64, 128, 256, 512, or 1024.

In one example, the flow chart 80 is executed in real-time. For example,a frame received as part of the “Receive Compressed Frame” step 81 isimmediately handled (as practical), and processed ‘as it happens’ asdescribed in the flow chart 80 fast enough to keep up with the framereceiving rate. In one exemplary scenario, the full handling of areceived frame as part of the “Receive Compressed Frame” step 81 iscompleted before the completion of the receiving of a next receivedframe. Further, the average or temporary rate of the transmitting orusing the constructed frames as part of the “Transmit/Use ReconstructedFrame” step 85 is equal to, or higher than, the rate of frames receptionas part of the “Receive Compressed Frame” step 81. Any compressionherein may be a dictionary-based compression.

The arrangement 65 shown in FIG. 6 illustrates a single receivedcompressed frame 60 that is used to reconstruct a single original frame10 using a mapping functionality 67. In order to achieve a betterefficiency or a higher data rate, a single compressed frame may includecompressed information that is a compressed version of multiple payloadsassociated with multiple frames. Such an arrangement 90 is shown in FIG.9, where a single received frame 60 a, corresponding to the frame 60described above, includes three compressed payloads, designated as aPAYLOAD1 62 a, a PAYLOAD2 62 b, and a PAYLOADS 62 c, each maycorresponds to the payload 62 described above. First, the first payloadPAYLOAD1 62 a is fed (shown as a line 81 a) to the mapping functionality67, and an output uncompressed payload 12 a is used to reconstruct afirst original (uncompressed) frame 10 a. Second, the second payloadPAYLOAD2 62 b is fed (shown as a line 81 b) to the mapping functionality67, and an output uncompressed payload 12 b is used to reconstruct asecond original frame 10 b, and third, the third payload PAYLOAD3 62 cis fed (shown as a line 81 c) to the mapping functionality 67, and anoutput uncompressed payload 12 c is used to reconstruct a third originalframe 10 c. Such configuration may be particularly effective if M/N<3.For example, in case where M=64 and N=16, the payload size of the frame60 a may be 3*16=48 bits, which may be implemented as a frame of 64 bitspayload, and each reconstructed frame 10 a, 10 b, and 10 c includes a 64bits payload. Since the non-payload part of the compressed frame 60 aincludes a single header 61 a and a single trailer 63 a are used only aspart of the frame 60 a, the efficiency is improved over using three suchheaders and trailers.

While the configuration exampled in the arrangement 90 involvescompression of three frames into a single compressed frame, any numberof such compression may be used, such as including payloads of 2, 4, 5,6, 7, 8, 10, 15, 20, 50, 70, or 100 uncompressed frames.

Carrying or encapsulating of multiple payloads or frames as part of asingle message (such as a single packet) or in multiple messages (suchas multiple packets), or the carrying or encapsulating carrying a singlepayload or frame in a single message (such as a single packet) or inmultiple messages (such as multiple packets), may be according to anyOSI layer 3 (Network Layer) or Layer 4 (Transport Layer) standard ornon-standard protocol. In one example, the protocol may be according to,compatible with, based on, or use, ISO 15765-2 protocol, such as ISO15765-2:2004 ISO-TP (Transport Layer) standard.

Few of the methods described herein allows for carrying of frames over acommunication medium that are shortened in length/size, yet carrying therequired information, by using a compressed version of it. In oneexample, the shortened frames may be used to carry additionalinformation. For example, the arrangement 65 above describes the frame60 as carrying the payload 62 consisting of N bits or locations. Theprotocol used to carry the frame 60 may dictate a fixed payload lengthof Q bits, thus Q−N bits or location are vacated or not used. In thecase where the frame 10 is using the same protocol as the frame 60, thenQ=M, and the number of empty locations in the fame 60 may be calculatedas M−N. In such a case, an additional information field that uses up toQ−N (or M−N) bits may be carried over the compressed frame 60, inaddition to carrying the primary data that was compressed. In case wherethe additional information utilizes less than the Q−N (or M−N) bits, anaffective compression may still be achieved.

In a numerical example, the frames 60 and 10 are both using a protocolthat uses a fixed-length payload of 64 bits (Q=M=64). Assuming a bit (ordata rate) compression ratio of 4, the compressed payload 62 requiresonly (64/4=) N=16 bits, leaving up to 64−16=48 bits for carryingadditional information. Assuming only 16 bits are used for theadditional information, then the affective total payload carried in theframe 60 is 32 bits, reflecting an affective compression ratio of 2(=64/32). The frame 60 may then be carried as 32 bits only payload,providing both a compression benefit and the benefit of carryingadditional information.

An example of a frame 60 b that carries an additional information 100 ais illustrated in an arrangement 100 shown in FIG. 10, where theadditional information 100 a is designated as ‘CODE’ field. The codefield 100 a may carry information that may be related to the payload 62,may be related to the frame 60 b, or may be related to the communicationnetwork, protocol, or medium, carrying the frame 60 b. In one example,the code field 100 a is used for Layer-2 handling of the frame 60 b,such as adding features or functionalities that are not defined, or arenot mandatory, in the protocol used to carry the frame 60 b.Alternatively or in addition, the code field 100 a may be used forsupport, features, or functionalities relating to OSI Layer-3, Layer-4,Layer-5, Layer-6, or Layer-7.

In one example, the code field 100 a is used to carry metadata, whichmay relate to the payload 62 carried in the same frame, or metadata ofother information or file. Such metadata may be in XML format.Alternatively or in addition, additional information carried in theframe 60 b may be used for implementing any error detecting scheme, andthe code 100 a may include one or more parity bits, a checksum, or aCRC. The code 100 a may be used to detect errors in any information ormessage, such as in the whole frame 60 b, the whole frame 10, thepayload 62, or the payload 12. Alternatively or in addition, additionalinformation carried in the frame 60 b may be used for implementing anyerror correcting scheme, such as a Forward error correction (FEC), andthe code 100 a may include an Error-Correcting Code (ECC). The code 100a may then be used to correct errors in any information or message, suchas in the whole frame 60 b, the whole frame 10, the payload 62, or thepayload 12.

Alternatively or in addition, an authentication scheme may be used, andthe code field 100 a is used to carry information for supporting theauthenticity of the frame 60 b (or of the frame 10). For example, theauthentication scheme may use, or be based on, Message AuthenticationCode (MAC), Authenticated Encryption (AE), or digital signatures, andthe code carried in the code field 100 a may comprise a cryptographickey, a digital signature, or a MAC, such as HMAC. Further, additionalinformation may be carried in the code field 100 a for supporting theauthentication scheme, such as Encryption Key identification, replayattack countermeasures such as counters, Key exchange information suchas Random numbers, or supporting data if an additional frame isrequired, such as a frame sequence number. MAC may also be implementedby adding a known number to plaintext and then encrypting the wholeframe with optional additional information as described for the MACalgorithm.

Generally, the compression of the frame 10 to obtain a compressed frame60 may be performed by reversing the steps or direction of thede-compression scheme described herein. A schematic arrangement ormethod 110 of constructing by using decompression of the frame 60 froman obtained or received compressed frame 10 is shown in FIG. 11.

The M bits forming the payload 12 of the frame 10 are orderly extractedfrom the frame 10, and are fed as input 66 b, via a bus, a physicalconnection, or as software or firmware variable, to a coder block orfunctionality 111. For each value of the input 66 b, the coderfunctionality 111 assign a set of N bits, which are fed via output 66 ato form the payload 62 of the compressed frame 60.

The mapping functionality 111 may be implemented using a memory 111 a asshown in an arrangement 110 a shown in FIG. 11a , where the memory 111 aserves as a Look-Up Table (LUT). In such a configuration, the input Mbits 66 b are used as an input providing an address to the memory 111 a,and the data stored at the input address is the N bits output 66 a.

In one example, the compression is stateless. Hence not dependent uponany former data, but rather may be represented as a combinatorial logicapplied to the input M bits 66 b, to produce the N bits output 66 a.Such combinatorial logic may be implemented using logic gates thatperform a logical operation on one or more binary inputs and producesbinary outputs.

Logic gates are primarily implemented using diodes or transistors actingas electronic switches. With amplification, logic gates can be cascadedin the same way that Boolean functions can be composed, allowing theconstruction of a physical model of all of Boolean logic, and therefore,all of the algorithms and mathematics that can be described with Booleanlogic. Logic circuits include such devices as multiplexers, registers,Arithmetic Logic Units (ALUs), and computer memory. In modern practice,most gates are made from field-effect transistors (FETs), particularlymetal-oxide-semiconductor field-effect transistors (MOSFETs). Compoundlogic gates AND-OR-Invert (AOI) and OR-AND-Invert (OAI) are oftenemployed in circuit design because their construction using MOSFETs issimpler and more efficient than the sum of the individual gates.

Hence, alternatively or in addition to using a memory, a PLD 111 a maybe used for obtaining the required N bits output 66 a as a function ofthe M bits input 66 b. For example, the lookup table functionality maybe implemented with a multiplexer whose select lines are driven by theaddress signal and whose inputs are the values of the elements containedin the array. These values can either be hard-wired, as in an ASIC whichpurpose is specific to a function, or provided by D latches which allowfor configurable values. An n-bit LUT can encode any n-input Booleanfunction by storing the truth table of the function in the LUT. This isan efficient way of encoding Boolean logic functions.

In the example shown in the arrangement 110 a, a hardware onlyimplementation may be used to implement the coder functionality 111,such as a memory or PLD 111 a. Alternatively or in addition, a coderfunctionality 111 b may be based on a processor 64 and a memory 69 asshown in an arrangement 110 b in FIG. 11b . The received M bits on input66 b are stored in a temporary input memory 68 b, which may be aregister, a shift register, a buffer, or any other memory suitable tostore the received N bits. The memory 69 includes firmware or softwarefor operating the processor 64, and further store the transfer functionrelating the compression, so that the processor 64 may apply thecompression information stored in the memory 69 to the data in theregister 68 b, and provide an output N bits to an output register 68 a(or other temporary memory), to be fed to the output 66 a. For example,the processor 64 may calculate a bit at a time and sequentially writethe calculated bits to the register 68 a.

The compression scheme herein assumes that the number of possiblepermutations of the payload 12 having M bits is equal or less than2^(N), and thus may be represented by N bits payload 62. However, whilein general this may be the case, occasionally (preferably seldom) areceived payload may be beyond the expected 2^(N) possible permutations.In such a case, the described compression may not be viable. Handlingsuch a preferably rare case is described as part of an arrangement 110 cshown in FIG. 11c . When a received payload 12 cannot be compressed, itmay be copied without any manipulation or compression to an output‘compressed’ frame 60 c (that is actually uncompressed), that furthercomprises a respective suitable header 61 c and a respective suitabletrailer 63 c. The coder 111 c is actually a 1:1 (same to same unchangedmapping) mapper that only transfer the payload 12 without anymanipulation or change to the output frame 60 c. In order to notify thereceiver that the frame 60 c comprises the unchanged or uncompressedpayload 12, the frame may further include an indicator ‘Uncompress Bit’101 (generated by the 1:1 coder 111 c). For example, when this bit isset, it represents that the payload 12 carried is the original one andis thus uncompressed, while when this bit is reset, it represents thatthe payload 62 carried in the original one and is thus compressedaccording to rules described herein. The expanding of the frame 60 c bya receiver is illustrated in an arrangement 100 a shown in FIG. 10a .Upon recognizing the receipt of the frame 60 c having the indicator bit101, the 1:1 mapping 67 c functionality is employed, which ignore anyother rules but only transfer the received payload 12 unchanged to theuncompressed original frame 10. The compression efficiency is reducedaccording to the number of frames having payloads that cannot becompressed. For example, in the case the number of payloads that cannotbe compressed is 1% of the received frames, than the compressionefficiency is reduced by 1%.

The ‘Q-Location Compression’ flow chart 140 d shown in FIG. 14d assumesthat the number of possible permutations of the Q locations in theuncompressed payload 12 is equal or less than 2^(Q-1), and thus may berepresented by Q−1 (or less) bits in payload 62. However, while ingeneral this may be the case, occasionally (preferably seldom) areceived payload may include a value in the selected Q locations that isbeyond the expected 2^(Q-1) possible values. In such a case, thedescribed compression may not be viable. For example, in case of 3locations based compression, the three locations (r,p,q) involves eightpossible values or variants are (0,0,0), (0,0,1), (0,1,0), (0,1,1),(1,0,0), (1,0,1), (1,1,0) and (1,1,1). In case only 4 values areexpected, such as (0,0,0), (0,1,1), (1,0,1) and (1,1,1), then these 4values may be represented by 2 bits, such as (r, q), and the value oflocation 1 may be calculated from these 2 values. However, in case wherea received payload includes the value (1,1,0) in the three locations(r,p,q), the mechanism to determine the value of the q location is notsuitable anymore.

Handling such a preferably rare case is described as part of anarrangement 110 d shown in FIG. 11d . When a set of locations (such asthree locations (r,p,q)) in the received payload 12 cannot be properlycompressed, a bit in a location (or few bits in few locations) whosevalue results in an error using the compression scheme is identified,and the location identification is added to a dedicated field in theoutput compressed frame. In the above example, the location of bit q isidentified and encapsulated into a specific field in an output frame. Inthe example of arrangement 110 d shown in FIG. 11d , an indicator field102 a is shown in an output compressed frame 60 d, having a respectiveheader 61 c and a respective trailer 63 c. The indicator field 102 a,generated 103 d by a coder 111 d, indicates the location of the bit thatis expected to result in an error value using the regular compressionscheme. The coder 111 d may include the functionality of any coderdescribed herein, in addition to handling the case where the inputpayload is not part of the expected range designed or planned to beproperly compressed. In the example of the frame 60 d, the field 102 aincludes only three bits, thus may identify only up to 8 locations(M−N=8) in the uncompressed payload 12. Any number of bits may beequally used, for example based on the number of locations that arereduced as part of the compression process. For example, in case ofM−N=16, 4 bits may be required, and in case of M−N−32, 5 bits may berequired. The value of the bit (location) identified by the locationfield 102 a is provided by a separate Uncompressed Bit Value indicatorbit 102 b. The value of the bit in the location identified by the field102 a is determined by the value 102 b set 103 e by the coder 111 d, andoverruling or bypassing the compression scheme determined. In theexample above, the value of the location q is set by the value carriedin the bit value 102 b and not based on the values of locations (r,p).

The expanding of the frame 60 d by a receiver is illustrated in anarrangement 100 b shown in FIG. 10b . Upon recognizing the receipt ofthe frame 60 d having the indicator location bits 102 a, a mappingfunctionality 67 d is employed, which performs the mapping functionalityas described herein, except for the location identified by the field 102a. A single bit mapping functionality 105 that is part of the mapper 67d use the bit value 103 b carried in the field 102 b to determine 104the value of the bit in the location indicated 103 a by the field 102 a.In the example shown in the arrangement 100 b, the location a_(M-3) 12 fis identified in the field 102 a, and as such its value is set 104 bythe bit value 102 b, and not by the compression scheme. The compressionefficiency is reduced according to the number of frames having locationsthat cannot be compressed according to the regular compression schemeherein. While the arrangement 110 d in FIG. 11d and the correspondingarrangement 100 b in FIG. 10b are exampled using a single field 102 athat identify a single location whose value is determined according tothe value carried in the Bit Value field 102 b, any number of locationsmay be similarly identified, and their corresponding values may bedetermined using multiple bit value locations or fields.

The location field 102 a, the bit value field 102 b, and the uncompressbit indicator 101, includes information that allows for overcomingissues in the compression scheme. In addition to support the case wherethe defined compression scheme is not suitable or provides an erroneousresult, such fields or indicators may be used for other purposes forsupplementing, supporting, or correcting used compression schemes. Inone example, such fields or indicator may be in addition to the field orindicators that are part of the frames (such as frames 10 or 60)standard structure. Alternatively or in addition, such fields orindicator may be part of, or may use, the field or indicators that areintegral part of the frames (such as frames 10 or 60) standardstructure. In the example of using CAN bus standard, the DLC field maybe used, and may include, may consists of, or may be indicator of, thelocation field 102 a, the bit value field 102 b, the uncompress bitindicator 101, or any combination thereof.

An example of a flow chart 130 of compressing a frame to form acompressed version is shown in FIG. 13, which is in general the reverseorder of the flow chart 80 shown in FIG. 8. An uncompressed frame, suchas the frame 10 described in FIG. 11, is received as part of a “ReceiveUncompressed Frame” step 131. The frame may be received from acommunication medium, using any physical layer (OSI Layer 1) standard orprotocol, such as the medium 16 shown in the arrangement 40 in FIG. 4,and may use a transceiver such as the transceiver 43 a in the device 41a. The received uncompressed frame is Layer-2 handled, such as by aframer or controller 57 a as part of the device 56 a shown in FIG. 5.The payload 12 is identified and extracted as part of an “ExtractPayload” step 132. The extracted payload 12 is then compressed orencoded into an output that provides the compressed payload 62 as partof a “Map/Code Payload” step 133. The compressed payload 62 is thenembedded to form the compressed frame 60, using Layer-2 handling, aspart of a “Construct Frame” step 134, and the constructed frame 60 maybe used as part of a “Transmit/Use Constructed Frame” step 135. Forexample, the reconstructed frame 60 may be transmitted over acommunication medium using any physical layer scheme, so it may bereceived as part of the “Receive Compressed Frame” step 81.

The compressed frame 60 formed as part of the “Construct Frame” step134, may be according to, or based on, a protocol, such as any OSILayer-2 protocol, that may be the same or different from the protocolused by the compressed frame 60 as part the “Receive Uncompressed Frame”step 131. In one example, the flow chart 130 is executed in real-time.For example, a frame received as part of the “Receive UncompressedFrame” step 131 is immediately handled (as practical), and compressed‘as it happens’ as described in the flow chart 130 fast enough to keepup with the frame receiving rate. In one exemplary scenario, the fullhandling of a received frame as part of the “Receive Uncompressed Frame”step 131 is completed before the completion of the receiving of a nextreceived frame. Further, the average or temporary rate of thetransmitting or using the constructed frames as part of the“Transmit/Use Constructed Frame” step 135 is equal to, or higher than,the rate of frames reception as part of the “Receive Uncompressed Frame”step 131.

A compression scheme typically requires compression rules or codinginformation that is shared by both the compressor and the de-compressor,used by the compressor for compressing the pre-compressed data into thecompressed data, and used by the de-compressor for de-compressing thecompressed data back into the pre-compressed data, such as by themapping functionality 67 that is described as part of the arrangement 65shown in FIG. 6. Such compression rules or coding information issometimes referred to as a ‘dictionary’. For example, the compressionrules or coding information may be a simple memory-based mapping that isstored in a memory, such as in the memory or PLD 67 a that is describedas part of the arrangement 65 a shown in FIG. 6a , stored in the memory69 used the processor 64 that are described as part of the arrangement65 b shown in FIG. 6b , or implemented as logic circuits 72 that isdescribed as part of the arrangement 70 shown in FIG. 7.

In one example, a forming of a coding information 160 (described in FIG.16) is described as part of a flow chart 140 shown in FIG. 14. As partof a first step “Obtain Samples” step 141, all possible or expectedpossibilities or combinations of the information to be compressed areobtained. For example, all possible or expected possibilities orcombinations of the payload 12 of the frame 10 may be involved. Suchcombination set may be formed analytically. For example, when a specificprotocol is used that defines specific fields, specific values in thefields and cross-correlation between values in various fields, thepossible combinations may be calculated. Alternatively or in addition, asimulation may generate possible or forecast values of the informationto be compressed. Preferably, the samples are obtained by a realimplementation, such as in a specific application or installation.

Next, as part of a “Minimize” step 147, the minimum set of combinationsis formed. For example, redundant samples, such as when two or moresamples are identical, only one sample combination (or value) may beused as a representative of the multiple occurrences. An example of aminimum set of combinations for the payload 12 of the frame 10 isdescribed in a table 150 shown in FIG. 15. The columns represent thevarious locations in the payload 12, including the first (such as theLSB) location or bit a₀ 12 a, the second location or bit a₁ 12 b, thethird location or bit a₂ 12 c, the fourth location or bit a₃ 12 d, thelast (such as the MSB) location or bit a_(M-1) 12 h, the one before thelast location or bit a_(M-2) 12 g, and the second before the lastlocation or bit a_(M-3) 12 f, as well as a location or bit a₉ 12 i, alocation or bit a₁₀ 12 j, and a location or bit a_(M-4) 12 k. Otherlocations or bits are not shown for the sake of simplicity.

The number of samples obtained as part of the “Obtain Samples” step 141,or the of samples remaining after removing redundancies as part of the“Minimize” step 147, may be equal to, less than, or higher than, 3, 4,5, 7, 10, 15, 20, 30, 50, 100, 200, 500, 1,000, 2,000, 5,000, 10,000,20,000, 50,000, 100,000, 200,000, 500,000, or 1,000,000. Alternativelyor in addition, the number of samples obtained as part of the “ObtainSamples” step 141, or the of samples remaining after removingredundancies as part of the “Minimize” step 147, may be equal to, lessthan, or higher than, 0.1%, 0.2%, 0.5%, 1%, 2%, 3%, 5%, 10%, 15%, 20%,30%, or 50% of the possible pre-compression combinations of 2^(M), ormay be equal to, less than, or higher than, 0.1%, 0.2%, 0.5%, 1%, 2%,3%, 5%, 10%, 15%, 20%, 30%, or 50% of the possible post-compressioncombinations of 2^(N).

The minimized non-overlapping ‘p’ combination samples are shown in rowsof the table 150. A first (top) row 151 a shows a first possiblecombination, a second row 151 b shows a second possible combination, athird row 151 c shows a third possible combination, and a fourth row 151d shows a fourth possible combination. Another exemplary row 151 e showsanother possible combination numbered as 32^(nd), and the last row 151 pshows a last possible combination. It is assumed that the number ‘p’ ofthe possible non-redundant combinations is less than 2^(M), thusallowing a compression and representation by less than M bits. In theexample above, p<2^(N) or p=2″, allowing for potential compressing to Nbits, where N<M. For example, in case of equal or less than 64 possiblecombinations, the compressed data may include only 6 bits.

Before starting the compression coding scheme, all the locations or bitsof the payload 12 are considered active and carrying meaningfulinformation, and thus all locations or bits are assigned ‘S’ value(S=Stay) as shown in the first row 161 a of the coding table 160 shownin FIG. 16.

Alternatively or in addition, the elementary transformation is not acoding (01→0, and 10→1), but rather an invertible (bijective) functionsuch as (00→01, 01→00, 10→10, 11→11), as shown in the coding table 160 ashown in FIG. 16a . The total transformation (without the columnelimination/removing, such as the final column number is the same) isinvertible also for the data, which does not correspond to the trainingdata. Such total transformation may be applied also to anyuncompressible data, and when decompressed, the uncompressed bits may bedetected in the marked (“to be removed”) columns, since our compressionis lossless.

The first stage (denoted J=1 since locations are analyzed individually)of the compression coding involves individual checking of the locations(or bits), and ignoring any possible correlation or redundancy betweenthem, as is performed as part of a “(J=1) 1-Location Compression” step142, which is further detailed in a flow chart 140 a shown in FIG. 14a .All locations of the information, such as the M locations (or bits) ofthe payload 12 are individually checked. The values of each of thelocation is checked throughout the all possible samples (p samples inthe example of the table 150) as part of a “Check Location” step 142 a.As part of a “All ‘1’ or ‘0’?” step 142 b, it is verified if all samplescarry the same value for the discussed location, such as all values are‘0’ or ‘1’. If there are mixed values in the samples, such as at leastone ‘0’ and at least one ‘1’ values, the location status is unchanged(such as ‘S’ in the table 160), and the next location is considered aspart of a “Next Location” step 142 c. However, in case where all valuesare the same (either ‘1’ or ‘0’), then the location affectively carriesno meaningful information, and as such may be removed and not betransmitted as part of the compression, as part of a “Modify Samples”step 142 e. As a substitute, a corresponding coding value (either ‘1’ or‘0’) may be used, as part of a “Mark as ‘1’ or ‘0’” step 142 d. In theexample of the table 150 shown in FIG. 15, the second location a₁ 12 bcarries ‘0’ in all the p samples, the location a₉ 12 i carries ‘1’ inthe p samples, and the location a_(M-3) 12 f carries ‘0’ in all the psamples. As a result, the coefficients after the first stage of1-Location based compression for the location a₁ 12 b is assigned as‘0’, for the location a₉ 12 i is assigned as ‘1’, and for the locationa_(M-3) 12 f is assigned as ‘0’, as shown in a second row 161 b in thetable 160. Further, the respective three locations location a₁ 12 b, a₉12 i, and a_(M-3) 12 f are removed from the samples table 150, resultinga new table 150 a shown in FIG. 15a , and are ignored and are not usedin any further compression stage. Thus the current compression (afterthe first stage) clearly provide a compression by reducing the number oflocations to be carried by 3, from uncompressed M locations to carryingcompressed M−3 locations.

After the first stage (corresponding to J=1) is completed, a criterion(or multiple criteria) are checked as part of a “Compression CriteriaMet?” step 143. If a pre-set criterion is met, no further compressionactivity are required, and the coding process ends at a “END” step 144,and the coding values in row 161 b are used for further data compressionor de-compression. However, in a case where the pre-set criterion is notmet when checked as part of the “Compression Criteria Met?” step 143,then J is incremented to 2 as part of a “J←−2” step 145, correspondingto the starting of the second stage of the coding (J=2).

Various criterions may be used as part of the “Compression CriteriaMet?” step 143. In one example, a pre-set value of the number of stagesto be performed is determined or set, and upon completing the set numberof stages the coding process is determined as completed. For example, ina case where the criterion is using a first stage (J=1) coding only, theprocess stops after completing the “(J=1) 1-Location Compression” step142, at the “END” step 144. Alternatively or in addition, the criterionmay relates to the success or failure in the compression coding in theprevious stage. For example, a minimum or maximum threshold may be set,and the coding process ends based on comparing with the set threshold,such as being below or above the set threshold. Such a threshold mayrelates, in one example, to the number of locations that were eliminatedas part of the last stage or in total in all the previous stages. Anabsolute number of locations may be used, such as where the threshold isequal to, less than, or higher than, 2, 3, 5, 7, 10, 15, 20, 30, 50,100, 200, 500, or 1000 locations. For example, if the threshold is aminimum of 5 column, and the locations eliminated in the last stage is7, than the criterion is satisfied and no more processing is required,while if the locations eliminated in the last stage is 5, than thecriterion is not satisfied and more processing is required to improvethe compression scheme. Similarly, if the threshold is a minimum of 15column, and the locations totally eliminated in all previous stages is20, than the criterion is satisfied and no more processing is required,while if the totally eliminated locations 10, than the criterion is notsatisfied and more processing is required to improve the compressionscheme. Alternatively or in addition, a compression ratio may be usedfor a stopping criterion. For example, a number of eliminated locationsrelative to the pre-compression number of locations or of the number oflocations before the last stage processing is performed. For example,the threshold may be equal to, less than, or higher than, 1%, 2%, 3%,5%, 7%, 10%, 15%, 20%, 25%, 30%, or 50%, of the M locations.

At a first time when a “J-Location Compression” step 146 is executed, Jequals 2, corresponding to stage 2 of the coding process. This stageinvolves comparing pairs of column, to check for redundancytherebetween, and is described in further detail in a flow chart 140 bshown in FIG. 14b . Every possible pair of locations is checked as partof a “Check 2 Locations” step 149 a. In case of M locations, there asM*(M−1)/2 possible pair to check. In an example of M=3 (designated asa₀, a₁, and a₂), there are three possible pairs, namely (a₀, a₁), (a₀,a₂), and (a₁, a₂). Similarly, in an example of M=4 (designated as a₀,a₁, a₂, and a₃), there are six possible pairs, namely (a₀, a₁), (a₀,a₂), (a₀, a₃), (a₁, a₂), (a₁, a₃), and (a₂, a₃).

Any pair of locations in the samples may be the same, may becomplementary, or may be different. As part of a “Same orComplementary?” step 149 b, each of the possible pairs are checked to bethe same or complementary in all the samples. In case where thelocations in the checked pair are not the same and are notcomplementary, the next pair is selected as part of a “Next 2 Locations”step 149 c and then checked as part of the “Same or Complementary?” step149 b, until all possible location pairs are checked. In the case wherea pair of locations was found to be the same, then one of the locationsis redundant and does not carry any additional information, and thus maybe eliminated, and may be later constructed by copying the remaininglocation, as part of a “Modify Samples” step 149 e. In such a case, therespective coefficient in the code relating to the eliminating locationmay be set to ‘0’ as part of a “Mark Coefficient as ‘1’ or ‘0’” step 149d. Similarly, in the case where a pair of locations was found to be thecomplementary, then one of the locations is redundant and may beeliminated, and may be later constructed by copying and inverting thevalues of the remaining location. In such a case, the respectivecoefficient in the code relating to the eliminating location may be setto ‘1’ as part of the “Mark Coefficient as ‘1’ or ‘0’” step 149 d. Forexample, the eliminated location may be reconstructed by applying a XORfunction with the respective coefficient to the remaining location.

In the example of table 150 a shown in FIG. 15a , it is exampled thatthe location a_(M-4) 12 k is the same as the location a₀ 12 a, havingthe same value for all bits in the ‘p’ rows (samples). Hence, thelocation a_(M-4) 12 k is redundant and may be eliminated, and may beconstructed merely by copying the content of the location a₀ 12 a.Hence, the third row that represents the status after the second stagein the table 160 shown in FIG. 16, the coefficient relating to thelocation a_(M-4) 12 k is marked as C0=0, where the ‘0’ suffix indicatingthat this location may be constructed by using the location a₀ 12 a, andthe value ‘0’ indicates that the same values as in the location a₀ 12 aare to be used in the construction. Further, in the example of table 150a shown in FIG. 15a , it is exampled that the location a₂ 12 c is thecomplementary to the location a₀ 12 a, having the complement value forall bits in the ‘p’ rows (samples). Hence, the location a₂ 12 c isredundant and may be eliminated, and may be constructed merely bycopying and inverting the content of the location a₀ 12 a. Hence, thethird row that represents the status after the second stage in the table160 shown in FIG. 16, the coefficient relating to the location a₂ 12 cis marked as C0=1, where the ‘0’ suffix is indicating that this locationmay be constructed by using the location a₀ 12 a, and the value ‘1’indicates that the complement values of the location a₀ 12 a are to beused in the construction. Since the two locations a₂ 12 c and a_(M-4) 12k do not carry any additional information and can be formed from thevalues in the location a₀ 12 a, they can be eliminated from any furtherconsideration, as illustrated in a table 150 b shown in FIG. 15 b.

An example of similar handling of 3 locations is described in a flowchart 140 c shown in FIG. 14c . For example, the flow chart 140 c may beexecuted as part of the “J-Location Compression” step 146 in the flowchart 140 upon arriving at this step at the third stage where J=3. In a“Check 3 Locations” step 149 a′ (corresponding to the “Check2-Locations” step 149 a or the “Check Location” step 142 a). In general,three locations in the samples may include 8 variants—Assuming threelocations (r,p,q), then the eight possible values or variants are(0,0,0), (0,0,1), (0,1,0), (0,1,1), (1,0,0), (1,0,1), (1,1,0) and(1,1,1). However, in case of a correlation between the locations, onlyfour or less variants may actually be found in the sample. In such acase, 2 bits may be used to represent the four possible variants,allowing for reduction from three to two locations, where the thirdcolumn is removed, and may be constructed from the other two locations.The number of variants of the three locations checked is determined aspart of a “4 or Less Variants?” step 149 b′, and upon determining thatmore than 4 variants exists in the samples for the checked threelocations, other three locations are selected from the M locations aspart of a “Next 3 Locations” step 149 c′, and then are checked as partof the “Check 3 Locations” step 149 a′. The checking may continue untilall possible three-set locations are checked, and the number of suchpossible sets may be calculated as M!/(3!*(M−3)!). For example, if M=4then the number of sets to check is 4, and for M=5 the number of sets tocheck is 10.

In one example, the three locations checked as part of the “Check 3Locations” step 149 a′ are locations a₃ 12 d, a₁₀ 12 j, and a_(M-2) 12g. As shown in the table 150 b, there are four variants or valuesassociated with three-location set (a₃, a₁₀, a_(M-2)), namely the valueset (1,1,0) shown in the sample or row #1 151 a and in the sample or row#32 151 e, the value set (0,1,0) shown in the sample or row #2 151 b,the value set (1,0,1) shown in the sample or row #3 151 c and in thesample or row #p 151 p, and the value set (0,0,1) shown in the sample orrow #4 151 d. Clearly the value of the location a_(M-2) 12 g is ‘1’ onlywhen the set (a₃, a₁₀) equal (0,0) or (1,0), and can be written as aBoolean expression !a₃*!a₁₀+a₃*!a₁₀ (where ‘!’=‘NOT’), hence thelocation a_(M-2) 12 g is redundant and may be removed (and later may becalculated based on the values of the locations a₃ 12 d, a₁₀ 12 j), aspart of a “Modify Samples” step 149 e′, as shown in a table 150 c shownin FIG. 15c . The compression code 160 may be updated, as part of a“Assign Coefficients” step 149 d′, as shown in a row 161 d to reflectthe coefficient of the location a_(M-2) 12 g as C(3, 10)={0,2}, wherethe prefixes ‘(3,10)’ indicates that this location may be obtained basedon location a₃ 12 d and a₁₀ 12 j, and the suffix {0,2} indicates thatthe location is logic ‘1’ only when the set (a₃, a₁₀) equals (0,0)=0d or(1,0)=2d.

In the above example for the case of less than 4 variants, one of thelocations is removed as being redundant and is being calculated from theother two locations in the set using a Boolean expression. Alternativelyor in addition, the four variants may be assigned any two bits, and theBoolean expression may be calculated accordingly. For example, the fourvariants of the checked locations may be arbitrarily assigned two bits.For example, the value set (1,1,0) may be assigned (0,0) (=0d), thevalue set (0,1,0) may be assigned (0,1) (=1d), the value set (1,0,1) maybe assigned (1,0) (=2d), and the value set (0,0,1) may be assigned (1,1)(=3d). In the above example, the coefficient of the location a_(M-2) 12g may be C(3,10)={2,3}. Further, the values carried in the locations set(a₃, a₁₀) are changed to reflect the assigned values of the two bits, asshown in the table 150 d shown in FIG. 15d . In such a case, thecompression code 160 shown in FIG. 16 includes the mapping code, statingthat the set (a₃, a₁₀)=(0,0) corresponds and maps the three locations(a₃, a₁₀, a_(M-2)) to (1,1,0), the set (a₃, a₁₀)=(0,1) corresponds andmaps the three locations (a₃, a₁₀, a_(M-2)) to (0,1,0), the set (a₃,a₁₀)=(1,0) corresponds and maps the three locations (a₃, a₁₀, a_(M-2))to (1,0,1), and the set (a₃, a₁₀)=(1,1) corresponds and maps the threelocations (a₃, a₁₀, a_(M-2)) to (0,0,1). Such a mapping is shown markedas ‘*’ in a row 161 d′ in the table 160.

The general case of checking Q locations, as part of stage J=Q, isexampled as a flow chart 140 d shown in FIG. 14d . As part of a “Check QLocations” step 149 a″, Q locations are selected for checking redundancytherebetween. In case of M total locations (at the beginning or aftercompression in previous stages), there are M!/[(Q!)*(M−Q)!]possibilities of selecting Q locations from the M locations. As part ofa “2^(Q-1) or Less Variants?” step 149 b″, the number of variants in thesamples is checked. In a case where the number of variants is above2^(Q-1), there is no redundant location, and a next Q locations set isselected as part of a “Next Q Locations” step 149 c″ for checking themas part of the “Check Q Locations” step 149 a″. However, in case ofredundancy, one of the locations is removed, as part of a “ModifySamples” step 149 e″, and the compression information, either as Booleanexpression of the remaining locations or by assigning distinct numbersto the found variants, as part of an “Assign Coefficients” step 149 d″.

In the case where the locations are being modified by assigning adistinct number to each of the variant that is found in the samples set,the modified samples may be used as a starting samples set, and then theprocess may be repeated to the newly formed samples set, trying tofurther compress the locations. For example, if the newly formedlocation values a3 12 d is the same as the location a_(M-1) 12 h, asshown in the table 150 d, then the location a_(M-1) 12 h may be removedas discussed regarding the 1-Location compression above in the flowchart 140 a shown in FIG. 14a . Such iterative process is shown in aflow chart 140 e shown in FIG. 14-1, which is based on the flow chart140 shown in FIG. 14. After the completion of a compression in the“J-Location Compression” step 146, it is checked if samples values (notonly removing the redundant locations) have been modified, as part of a“Samples Modified?” step 146 a. If indeed samples values have beenmodified, it may be that 2-Location compression may be used to furtherremove one of the modified locations, thus the second stage (J=2) isrepeated at the “J←2” step 145, applied to the new updated samples set.

As can be shown in the compression code table 160, after the abovecompression steps only four locations (columns) are not removed(designated as ‘S’=Stay) and are part of the post-compression locationsand are to be sent as compressed data, namely a₀ 12 a, a₃ 12 d, a₁₀ 12j, and a_(M-1) 12 h. An example of an actual compression is shown inFIGS. 12 and 12 a. An actual data was collected from an actualinstallation of a CAN environment protocol (64-bit payload field), andafter minimization a distinct 80 samples were found, as presented inFIG. 12. After applying an example of the compression scheme describedherein, the 80 samples were found to be represented by 12 bits, as shownin FIG. 12 a.

The “Map/Code Payload” step 133 as part of the flow chart 130 shown inFIG. 13, generally performed by the coder 111, may include two steps, an“Identify Locations” step 133 a followed by a “Remove Locations” step133 b, as shown in FIG. 13. An example involving execution of thesesteps is shown in FIG. 17. As part of the “Identify Locations” step 133a, the bit locations in the received payload 12 (as part of the frame10) are segmented into two categories: Locations which remains after anycompression action and are transmitted as part of the compressed payload62, and locations having redundant values, that may be removed sincethey can be obtained by using the remaining bits, for example byemploying compression according to the flow chart 140 shown in FIG. 14,according to the flow chart 140 e shown in FIG. 14-1, according to theflow chart 140 a shown in FIG. 14a , according to the flow chart 140 hshown in FIG. 14b , according to the flow chart 140 c shown in FIG. 14c, according to the flow chart 140 d shown in FIG. 14d , according to anyother compression scheme, or any combination thereof. In the exampleshown in FIG. 17, the word or vector 170 represents the word thatcorresponds to the bit locations 161 d′, that is obtained after applyingthe exampled compression techniques (at step 3′) top the payload 161 ashown as part of the table 160 in FIG. 16. As shown, the only relevantuncompressed bit locations, from which the original ion formation may befully restored, are bit locations a₀ 12 a, a₃ 12 d, a₁₀ 12 j, anda_(M-1) 12 h, totaling 4 bits of the received M bits payload (N=4). Therest of the bit locations are not required to be transmitted and arereconstructed from the compressed payload 12 as part of the “MapPayload” step 83 generally performed by the Mapping functionality 67.The bit locations that are to be transmitted after compression are shownas part of a word ‘x’ 170 a. In one example, a mask vector of work 170 bmay be used, having ‘1’ in any bit location that is not removed as partof the compression, and ‘0’ in any bit location that is to be removed aspart of the compression.

The word or vector ‘x’ 170 a is M bits long, however the compressiongoal is to reduce the compressed word or vector length to N (N<M). Suchlength reduction is performed as part of the “Remove Locations” step 133b, in which the relevant bits that are to be sent after compression areshrink into a word or vector having N bit locations, thus achieving thecompression goal. In the example shown in FIG. 17, N=4, and thus apayload 170 c (corresponding to payload 62) of only 4 bits is generated,carrying only the minimum number of bits that allow to reconstruct theoriginal payload 12. Similarly, the “Map Payload” step 83 involves theopposite activity, where first the additional locations are added toform a payload having M bit location and embedding the received bits inthe appropriate bit locations, and then calculating the bit values ofthe locations that were removed as part of the “Remove Locations” step133 b.

The uncompressing actions are exampled in FIG. 17a , which is based onthe example shown in FIG. 17. The 4-bits vector or word 170 c(corresponding to the received payload 62) is first translated orconverted to the M-bits length word 170 a, having the received bits inthe proper bit locations. Then the rest of the bit locations arecalculated according to the compression rules to obtain the word 160(corresponding to the payload 12), which is the original payload beforethe compression.

The compacting the M-bit length word of the uncompressed payload 12before compression to the N-bit length word of the compressed payload 62after compression, such as from the word ‘x’ 170 a to the 4-bit lengthword 170 c shown in FIG. 17, performed as part of the “Remove Location”step 133 b, may be using any known technique of such compacting. Forexample, the word ‘x’ 170 a may be in a register that is shifted rightone bit at a time (together with the register holding the mask ‘m’ word170 b), and according to the corresponding value of the bit in the mask‘m’ word 170 b, the bit location value may be discarded (if therespective bit in ‘0’), or shifted to the output word 170 c (in therespective bit in ‘1’).

A collection of small programming tricks are described in a bookentitled: “Hacker's Delight”, Second Edition, by Henry S. Warren, Jr.,published 2013 by Pearson Education, Inc. [ISBN-13: 978-0-321-84268-8],which is incorporated in its entirety for all purposes as if fully setforth herein.

An example of a program (generalized extract) for compacting(compressing) a word ‘x’ 170 a using a mask ‘m’ 170 b, with minimumworst-case execution time, is provided in chapter 7-4 of the book, asfollows:

// ------------------------------ cut ----------------------------------unsigned compress2 (unsigned x, unsigned m) { unsigned r, s, b;     //Result, shift, mask bit.  r = 0;  s = 0 ;  do {   b = m & 1;   r = r |(x & b) << s) ;   s = s + b;   x = x >> 1;   m = m >> 1;  }while (m !=0);  return r; } // ---------------------------- end cut--------------------------------

Another example of a program (generalized extract) for compacting(compressing) a word ‘x’ 170 a using a mask ‘m’ 170 b, with substantialreduced number of instructions to be executed, is further provided inchapter 7-4 of the book, as follows:

#include <stdio.h> #include <stdlib.h> #include <time.h> char *binary(unsigned k);     // Is below. unsigned compress_left(unsigned x,unsigned m) {  unsigned mk, mp, mv, t;  int i;  x = x & m;     // Clearirrelevant bits.  mk = ~m >> 1;    // We will count 0's to left. printf(″\n\n      m = %s\n″, binary(m));  printf(″      x = %s\n″,binary(x));  for (i = 0; i < 5; i++) {   printf(″\ni = %d,  mk = %s\n″,i, binary(mk));   mp = mk {circumflex over ( )} (mk >> 1);    //Parallel prefix.   mp = mp {circumflex over ( )} (mp >> 2);   mp = mp{circumflex over ( )} (mp >> 4);   mp = mp {circumflex over ( )} (mp >>8);   mp = mp {circumflex over ( )} (mp >> 16);   printf(″After PP, mp =%s\n″, binary(mp));   mv = mp & m;      // Bits to move.  printf(″    mv = %s\n″, binary(mv));   m = m {circumflex over ( )} mv(mv << (1 << i));  // Compress m.   t = x & mv;   x = x {circumflex over( )} t | (t << (1 << i));    // Compress x.   printf(″   m = %s\n″,binary(m));   printf(″     x = %s\n″, binary(x));   mk = mk & ~mp;  } return x; } int errors; void error (unsigned x, unsigned m, unsignedgot, unsigned shdbe) {  errors = errors + 1;  printf(″Error for x =%08X, m = %08x, got %08X, should be %08X\n″,    x, m, got, shdbe); } intmain (void) {  int i, n;  unsigned r;  static unsigned test[ ] = {  0xFFFFFFFF, 0x80000000, 0x80000000,   0xFFFFFFFF, 0x0010084A,0xF8000000,   0xFFFFFFFF, 0x55555555, 0xFFFF0000,   0xFFFFFFFF,0x88E00F55, 0xFFF80000,   0x01234567, 0x0000FFFF, 0x45670000,  0x01234567, 0xFFFF0000, 0x01230000,   0xFFFFFFFF, 0xFFFFFFFF,0xFFFFFFFF,   0, 0, 0,   0, 0xFFFFFFFF, 0,   0xFFFFFFFF, 0, 0,  0x80000000, 0x80000000, 0x80000000,   0x55555555, 0x55555555,0xFFFF0000,   0x55555555, 0xAAAAAAAA, 0,   0x789ABCDE, 0x0F0F0F0F,0x8ACE0000,   0x789ABCDE, 0xF0F0F0F0, 0x79BD0000,   0x92345678,0x80000000, 0x80000000,   0x12345678, 0xF0035555, 0x13B00000, /* Was000004ec */   0x80000000, 0xF0035555, 0x80000000,  };  n=sizeof(test)/sizeof(test[0]);  printf(″compress left:\n″);  for (i = 0;i < n; i += 3) {   r = compress_left(test[i], test[i+1]);   if (r !=test[i+2])    error(test[i], test[i+1], r, test[i+2]);   }  if (errors== 0)   printf(″Passed all %d cases.\n″, n/3);  return errors; } /*Converts the unsigned integer k to binary character form with a blankafter every fourth digit. Result is in string s of length 39. Caution:If you want to save the string, you must move it. This is intended foruse with printf, and you can have only one reference to this in eachprintf statement. */ char * binary (unsigned k) {  int i, j;  staticchar s[40] = ″0000 0000 0000 0000 0000 0000 0000 0000″;  j = 38;  for (i= 31; i >= 0; i−−) {   if (k & 1) s[j] = ′1′;   else   s[j] = ′0′;   j =j − 1;   k = k >> 1;   if ((i & 3) == 0) j = j − 1;  }  return s; }

Similarly, the expanding action, such as from the word 170 c into theword 170 a shown in the FIG. 17a may use a program provided in chapter7-4 of the book, as follows:

/* Inverse of compress (right). */ #include <stdio.h> /* Inverse ofcompress2 (HD page 151). This version has no branches in the loop. Eightinsns in the loop, giving 8*32 + 2 = 258 insns worst case. */ unsignedexpand2(unsigned x, unsigned m) {  unsigned r, s, b;   // Result, shift,mask bit.  r = 0;  s = 0;  do {   b = m & 1;   r = r | ((x & b) << s);  s = s + 1;   x = x >> b;   m = m >> 1;  } while (m != 0);  return r; }

Alternatively or in addition, the expanding action, such as from theword 170 c into the word 170 a shown in the FIG. 17a may use anotherprogram provided in chapter 7-4 of the book, as follows:

// ------------------------------------------------- cut------------------------------------------------- unsignedexpand4(unsigned x, unsigned m) {  unsigned m0, mk, mp, mv, t;  unsignedarray[5];  int i;  m0 = m;       // Save original mask.  mk = ~m <<1;     // We will count 0's to right.  for (i = 0; i < 5; i++) {   mp =mk {circumflex over ( )} (mk << 1);       // Parallel suffix.   mp = mp{circumflex over ( )} (mp << 2);   mp = mp {circumflex over ( )} (mp <<4);   mp = mp {circumflex over ( )} (mp << 8);   mp = mp {circumflexover ( )} (mp << 16);   mv = mp & m;          // Bits to move.   array[i] = mv;   m = (m {circumflex over ( )} mv) | (mv >> (1 << i));    //Compress m.   mk = mk & ~mp;  }  for (i = 4; i >= 0; i−−) {   mv =array[i];   t = x << (1 << i);   x = (x & ~my) | (t & mv); //  x = ((x{circumflex over ( )} t) & mv) {circumflex over ( )} x;        //Alternative for above line.  }  return x & m0;   // Clear out extraneousbits. } // ---------------------------- end cut---------------------------- int errors; void error (unsigned x,unsigned m, unsigned got, unsigned shdbe) {  errors = errors + 1; printf(″Error for x = %08X, m = %08x, got %08X, should be %08X\n″,    x, m, got, shdbe); } int main (void) {  int i, n;  unsigned r; static unsigned test[ ] = { //  Data  Mask  Result 0x00000001,0x80000000, 0x80000000, // These first 4 cases will 0x0000001F,0x0010084A, 0x0010084A, // work with Allen's ″scatter″ 0x0000FFFF,0x55555555, 0x55555555, // function, because the 0x00001FFF, 0x88E00F55,0x88E00F55, // irrelevant HO bits are 0. 0xFFFFFFFF, 0x80000000,0x80000000, 0xFFFFFFFF, 0x0010084A, 0x0010084A, 0xFFFFFFFF, 0x55555555,0x55555555, 0xFFFFFFFF, 0x88E00F55, 0x88E00F55, 0x01234567, 0x0000FFFF,0x00004567, 0x01234567, 0xFFFF0000, 0x45670000, 0xFFFFFFFF, 0xFFFFFFFF,0xFFFFFFFF, 0, 0, 0, 0, 0xFFFFFFFF, 0, 0xFFFFFFFF, 0, 0, 0x80000000,0x80000000, 0, 0x55555555, 0x55555555, 0x11111111, 0x55555555,0xAAAAAAAA, 0x22222222, 0x789ABCDE, 0x0F0F0F0F, 0x0B0C0D0E, 0x789ABCDE,0xF0F0F0F0, 0xB0C0D0E0, 0x92345678, 0x80000000, 0, 0x12345678,0xF0035555, 0x50021540, 0x80000000, 0xF0035555, 0,  };  n =sizeof(test)/sizeof(test[0]);  printf(″expand2:\n″);  for (i = 0; i < n;i += 3) {   r = expand2(test[i], test[i+1]);   if (r != test[i+2])   error(test[i], test[i+1], r, test[i+2]);  }  printf(″expand4:\n″); for (i = 0; i < n; i += 3) {   r = expand4(test[i], test[i+1]);   if (r!= test[i+2])    error(test[i], test[i+1], r, test[i+2]);  }  if (errors== 0)   printf(″Passed all %d cases.\n″, n/3);  return errors; }

Any wired network herein may be a Personal Area Network (PAN), anyconnector herein may be a PAN connector, and any transceiver herein maybe a PAN transceiver. Alternatively or in addition, any network hereinmay be a Local Area Network (LAN) that may be Ethernet-based, antconnector herein may be a LAN connector, and any transceiver herein maybe a LAN transceiver. The LAN may be according to, may be compatiblewith, or may be based on, IEEE 802.3-2008 standard. Alternatively or inaddition, the LAN may be according to, may be compatible with, or may bebased on, 10Base-T, 100Base-T, 100Base-TX, 100Base-T2, 100Base-T4,1000Base-T, 1000Base-TX, 10GBase-CX4, or 10GBase-T; and the LANconnector may be an RJ-45 type connector. Alternatively or in addition,the LAN may be according to, may be compatible with, or may be based on,10Base-FX, 100Base-SX, 100Base-BX, 100Base-LX10, 1000Base-CX,1000Base-SX, 1000Base-LX, 1000Base-LX10, 1000Base-ZX, 1000Base-BX10,10GBase-SR, 10GBase-LR, 10GBase-LRM, 10GBase-ER, 10GBase-ZR, or10GBase-LX4, and the LAN connector may be a fiber-optic connector.Alternatively or in addition, any network herein may be a packet-basedor switched-based Wide Area Network (WAN), any connector herein may be aWAN connector, and any transceiver herein may be a WAN transceiver.Alternatively or in addition, any network herein may be according to,may be compatible with, or may be based on, a Serial PeripheralInterface (SPI) bus or Inter-Integrated Circuit (PC) bus.

Any processor or logic herein, such as the processor 64 may be based ona discrete logic or an integrated device, such as a processor,microprocessor or microcomputer, and may include a general-purposedevice or may be a special purpose processing device, such as an ASIC,PAL, PLA, PLD, Field Programmable Gate Array (FPGA), Gate Array, orother customized or programmable device. In the case of a programmabledevice as well as in other implementations, a memory is required. Anyprocessor herein may include a memory that may include a static RAM(random Access Memory), dynamic RAM, flash memory, ROM (Read OnlyMemory), or any other data storage medium. The memory may include data,programs, and/or instructions and any other software or firmwareexecutable by the processor. Control logic can be implemented inhardware or in software, such as a firmware stored in the memory.

Any one of the apparatuses described herein, such as a device, module,or system, may be integrated or communicating with, or connected to, thevehicle self-diagnostics and reporting capability, commonly referred toas On-Board Diagnostics (OBD), to a Malfunction Indicator Light (MIL),or to any other vehicle network, sensors, or actuators that may providethe vehicle owner or a repair technician access to health or stateinformation of the various vehicle sub-systems and to the variouscomputers in the vehicle. Common OBD systems, such as the OBD-II and theEOBD (European On-Board Diagnostics), employ a diagnostic connector,allowing for access to a list of vehicle parameters, commonly includingDiagnostic Trouble Codes (DTCs) and Parameters IDentification numbers(PIDs). The OBD-II is described in the presentation entitled:“Introduction to On Board Diagnostics (II)” downloaded on November 2012from:http://groups.engin.umd.umich.edu/vi/w2_workshops/OBD_ganesan_w2.pdf,which is incorporated in its entirety for all purposes as if fully setforth herein. The diagnostic connector commonly includes pins thatprovide power for the scan tool from the vehicle battery, thuseliminating the need to connect a scan tool to a power sourceseparately. The status and faults of the various sub-systems accessedvia the diagnostic connector may include fuel and air metering, ignitionsystem, misfire, auxiliary emission control, vehicle speed and idlecontrol, transmission, and the on-board computer. The diagnostics systemmay provide access and information about the fuel level, relativethrottle position, ambient air temperature, accelerator pedal position,air flow rate, fuel type, oxygen level, fuel rail pressure, engine oiltemperature, fuel injection timing, engine torque, engine coolanttemperature, intake air temperature, exhaust gas temperature, fuelpressure, injection pressure, turbocharger pressure, boost pressure,exhaust pressure, exhaust gas temperature, engine run time, NOx sensor,manifold surface temperature, and the Vehicle Identification Number(VIN). The OBD-II specifications defines the interface and the physicaldiagnostic connector to be according to the Society of AutomotiveEngineers (SAE) J1962 standard, the protocol may use SAE J1850 and maybe based on, or may be compatible with, SAE J1939 Surface VehicleRecommended Practice entitled: “Recommended Practice for a SerialControl and Communication Vehicle Network” or SAE J1939-01 SurfaceVehicle Standard entitled: “Recommended Practice for Control andCommunication Network for On-Highway Equipment”, and the PIDs aredefined in SAE International Surface Vehicle Standard J1979 entitled:“E/E Diagnostic Test Modes”, which are all incorporated in theirentirety for all purposes as if fully set forth herein. Vehiclediagnostics systems are also described in the International Organizationfor Standardization (ISO) 9141 standard entitled: “Roadvehicles—Diagnostic systems”, and the ISO 15765 standard entitled: “Roadvehicles—Diagnostics on Controller Area Networks (CAN)”, which are allincorporated in their entirety for all purposes as if fully set forthherein.

The physical layer of the in-vehicle network may be based on, compatiblewith, or according to, J1939-11 Surface Vehicle Recommended Practiceentitled: “Physical Layer, 250K bits/s, Twisted Shielded Pair” orJ1939-15 Surface Vehicle Recommended Practice entitled: “ReducedPhysical Layer, 250K bits/s, Un-Shielded Twisted Pair (UTP)”, the datalink may be based on, compatible with, or according to, J1939-21 SurfaceVehicle Recommended Practice entitled: “Data Link Layer”, the networklayer may be based on, compatible with, or according to, J1939-31Surface Vehicle Recommended Practice entitled: “Network Layer”, thenetwork management may be based on, compatible with, or according to,J1939-81 Surface Vehicle Recommended Practice entitled: “NetworkManagement”, and the application layer may be based on, compatible with,or according to, J1939-71 Surface Vehicle Recommended Practice entitled:“Vehicle Application Layer (through December 2004)”, J1939-73 SurfaceVehicle Recommended Practice entitled: “Application Layer—Diagnostics”,J1939-74 Surface Vehicle Recommended Practice entitled:“Application—Configurable Messaging”, or J1939-75 Surface VehicleRecommended Practice entitled: “Application Layer—Generator Sets andIndustrial”, which are all incorporated in their entirety for allpurposes as if fully set forth herein.

Any wired network herein may be a Local Area Network (LAN) to provide adata communication connection to a compatible LAN. For example, Ethernetconnection based on IEEE802.3 standard may be used, such as 10/100BaseT,1000BaseT (gigabit Ethernet), 10 gigabit Ethernet (10GE or 10 GbE or 10GigE per IEEE Std. 802.3ae-2002as standard), 40 Gigabit Ethernet (40GbE), or 100 Gigabit Ethernet (100 GbE as per Ethernet standard IEEEP802.3ba). These technologies are described in Cisco Systems, Inc.Publication number 1-587005-001-3 (6/99), “Internetworking TechnologiesHandbook”, Chapter 7: “Ethernet Technologies”, pages 7-1 to 7-38, whichis incorporated in its entirety for all purposes as if fully set forthherein. In such a case, a LAN transceiver or a modem may be used, suchas a Standard Microsystems Corporation (SMSC) LAN91C111 10/100 Ethernettransceiver, described in the Standard Microsystems Corporation (SMSC)data-sheet “LAN91C111 10/100 Non-PCI Ethernet Single Chip MAC+PHY”Data-Sheet, Rev. 15 (02-20-04), which is incorporated in its entiretyfor all purposes as if fully set forth herein.

The topology of any wired network herein may be based on, or may use,point-to-point, bus, star, ring or circular, mesh, tree, hybrid, ordaisy chain topology. Any two nodes may be connected in a point-to-pointtopology, and any communication herein between two nodes may beunidirectional, half-duplex, or full-duplex. Any medium herein maycomprise, or may consist of, an unbalanced line, and any signals hereinmay be carried over the medium employing single-ended signaling, thatmay be based on, may be according to, or may be compatible with, RS-232or RS-423 standards. Alternatively or in addition, any medium herein maycomprises, or may consist of, a balanced line, and any signals hereinmay be carried over the medium employing differential signaling, thatmay be based on, may be according to, or may be compatible with, RS-232or RS-423 standards. Any communication over a medium herein may useserial or parallel transmission.

Any vehicle herein may be a ground vehicle adapted to travel on land,such as a bicycle, a car, a motorcycle, a train, an electric scooter, asubway, a train, a trolleybus, and a tram. Alternatively or in addition,the vehicle may be a buoyant or submerged watercraft adapted to travelon or in water, and the watercraft may be a ship, a boat, a hovercraft,a sailboat, a yacht, or a submarine. Alternatively or in addition, thevehicle may be an aircraft adapted to fly in air, and the aircraft maybe a fixed wing or a rotorcraft aircraft, such as an airplane, aspacecraft, a glider, a drone, or an Unmanned Aerial Vehicle (UAV). Anyapparatus or device herein may be used for measuring or estimating analtitude, a pitch, or a roll of the aircraft, and may be operative tonotify or indicate to a person that may be the vehicle operator orcontroller in response to the first distance (d1) or any functionthereof, the second distance (d2) or any function thereof, or theestimated first angle (α) or any function thereof. Alternatively or inaddition, any apparatus or device herein may be used for measuring orestimating the apparatus or device speed, positioning, pitch, roll, oryaw of the mobile apparatus or device.

Any apparatus or device herein may be operative to connected to, coupledto, communicating with, an automotive electronics in a vehicle, or maybe part of, or may be integrated with, an automotive electronics in avehicle. An Electronic Control Unit (ECU) may comprise, or may be partof, any apparatus or device herein. Alternatively or in addition, anyapparatus or device herein may consist of, may be part of, may beintegrated with, may be connectable to, or may be couplable to, anElectronic Control Unit (ECU) in the vehicle, and the Electronic ControlUnit (ECU) may be Electronic/engine Control Module (ECM), Engine ControlUnit (ECU), Powertrain Control Module (PCM), Transmission Control Module(TCM), Brake Control Module (BCM or EBCM), Central Control Module (CCM),Central Timing Module (CTM), General Electronic Module (GEM), BodyControl Module (BCM), Suspension Control Module (SCM), Door Control Unit(DCU), Electric Power Steering Control Unit (PSCU), Seat Control Unit,Speed Control Unit (SCU), Telematic Control Unit (TCU), TransmissionControl Unit (TCU), Brake Control Module (BCM; ABS or ESC), Batterymanagement system, control unit, or a control module. Alternatively orin addition, the Electronic Control Unit (ECU) may comprise, may use,may be based on, or may execute a software, an operating-system, or amiddleware, that may comprise, may be based on, may be according to, ormay use, OSEK/VDX, International Organization for Standardization (ISO)17356-1, ISO 17356-2, ISO 17356-3, ISO 17356-4, ISO 17356-5, or AUTOSARstandard. Any software herein may comprise, may use, or may be based on,an operating-system or a middleware, that may comprise, may be based on,may be according to, or may use, OSEK/VDX, International Organizationfor Standardization (ISO) 17356-1, ISO 17356-2, ISO 17356-3, ISO17356-4, ISO 17356-5, or AUTOSAR standard.

Any network herein may be a vehicle network, such as a vehicle bus orany other in-vehicle network. A connected element comprises atransceiver for transmitting to, and receiving from, the network. Thephysical connection typically involves a connector coupled to thetransceiver. The vehicle bus may consist of, may comprise, may becompatible with, may be based on, or may use a Controller Area Network(CAN) protocol, specification, network, or system. The bus medium mayconsist of, or comprise, a single wire, or a two-wire such as an UTP ora STP. The vehicle bus may employ, may use, may be compatible with, ormay be based on, a multi-master, serial protocol using acknowledgement,arbitration, and error-detection schemes, and may further usesynchronous, frame-based protocol. Further, any network herein may usean OSI layer 3 (Network Layer) or Layer 4 (Transport Layer) standard ornon-standard protocol. In one example, the protocol may be according to,compatible with, based on, or use, ISO 15765-2 protocol.

The network data link and physical layer signaling may be according to,compatible with, based on, or use, ISO 11898-1:2015. The medium accessmay be according to, compatible with, based on, or use, ISO11898-2:2003. The vehicle bus communication may further be according to,compatible with, based on, or use, any one of, or all of, ISO11898-3:2006, ISO 11898-2:2004, ISO 11898-5:2007, ISO 11898-6:2013, ISO11992-1:2003, ISO 11783-2:2012, SAE J1939/11_201209, SAEJ1939/15_201508, or SAE J2411_200002 standards. The CAN bus may consistof, may be according to, may be compatible with, may be based on, or mayuse a CAN with Flexible Data-Rate (CAN FD) protocol, specification,network, or system.

Alternatively or in addition, the vehicle bus may consist of, maycomprise, may be based on, may be compatible with, or may use a LocalInterconnect Network (LIN) protocol, network, or system, and may beaccording to, may be compatible with, may be based on, or may use anyone of, or all of, ISO 9141-2:1994, ISO 9141:1989, ISO 17987-1, ISO17987-2, ISO 17987-3, ISO 17987-4, ISO 17987-5, ISO 17987-6, or ISO17987-7 standards. The battery power-lines or a single wire may serve asthe network medium, and may use a serial protocol where a single mastercontrols the network, while all other connected elements serve asslaves.

Alternatively or in addition, the vehicle bus may consist of, maycomprise, be compatible with, may be based on, or may use a FlexRayprotocol, specification, network or system, and may be according to, maybe compatible with, may be based on, or may use any one of, or all of,ISO 17458-1:2013, ISO 17458-2:2013, ISO 17458-3:2013, ISO 17458-4:2013,or ISO 17458-5:2013 standards. The vehicle bus may support a nominaldata rate of 10 Mb/s, and may support two independent redundant datachannels, as well as independent clock for each connected element.

Alternatively or in addition, any vehicle bus herein may consist of, maycomprise, or may be based on, an avionics data bus standard, such asAircraft Data Network (ADN), Avionics Full-Duplex Switched Ethernet(AFDX), Aeronautical Radio INC. (ARINC) 664, ARINC 629, ARINC 708, ARINC717, ARINC 825, MIL-STD-1553, MIL-STD-1760, or Time-Triggered Protocol(TTP).

Alternatively or in addition, the vehicle bus may consist of, comprise,be compatible with, may be based on, or may use a Media Oriented SystemsTransport (MOST) protocol, network or system, and may be according to,may be compatible with, may be based on, or may use any one of, or allof, MOST25, MOST50, or MOST150. The vehicle bus may employ a ringtopology, where one connected element may be the timing master thatcontinuously transmits frames where each comprises a preamble used forsynchronization of the other connected elements. The vehicle bus maysupport both synchronous streaming data as well as asynchronous datatransfer. The network medium may be wires (such as UTP or STP), or maybe an optical medium such as Plastic Optical Fibers (POF) connected viaan optical connector. In one example, the vehicle bus may consists of,comprises, or may be based on, automotive Ethernet, may use only asingle twisted pair, and may consist of, employ, use, may be based on,or may be compatible with, IEEE802.3 100BaseT1, IEEE802.3 1000BaseT1,BroadR-Reach®, or IEEE 802.3bw-2015 standard.

Any of the methods and compression/de-compression schemes herein may beused to provide lossless compression that is based on statistics ofmessages or frames actually used in a specific application orinstallation. The compression/de-compression schemes herein typically isstateless and may not require any storing of any former messages orframes, but is performed on frame-by-frame basis. Further, thecompression/de-compression schemes herein may be implemented usinglow-sized memory and minimally increasing CPU workload or processingtime. In one example, the methods and compression/de-compression schemesherein may be used to shorten a message payload, such as in a CANprotocol, allowing for reduction of the overall traffic carried over thebus or network. Such shortening of a frame payload allows for inserting,without changing a frame limitation, a cryptographic signature theframe. The shortening of the frame may be used for adding additionalinformation in the frame without elongating it, such as information orcode for implementing additional features such as error detection, errorcorrection, encryption, authentication, and any other OSI Layer-3 orabove features or functionalities.

Any apparatus herein, may comprise any element or functionality,described in the “BACKGROUND” section above, and included in any of thedocuments incorporated therein. Further, any method or step herein maycomprise any element or functionality, or may execute any step, method,or action, described in the “BACKGROUND” section above, including in anyof the documents incorporated therein. In one example, any compressionherein may include, may comprise, ort may be based on, any compressionscheme described in the “BACKGROUND” section above including in any ofthe documents incorporated therein. Further, any method herein may beintegrated, used with, combined with, or coupled to, any feature orfunctionality described in the “BACKGROUND” section above, including inany of the documents incorporated therein.

Electronic circuits and components are described in a book by Wikipediaentitled: “Electronics” downloaded from en.wikibooks.org dated Mar. 15,2015, and in a book authored by Owen Bishop entitled:“Electronics—Circuits and Systems” Fourth Edition, published 2011 byElsevier Ltd. [ISBN—978-0-08-096634-2], which are both incorporated intheir entirety for all purposes as if fully set forth herein.

The term ‘message’ is used herein to include any type of information orone or more datagram, handled as a single, as a set or as a group ofdatagrams. The datagram may be a packet or a frame, or any other type ofgroup of data bytes (or bits) which represent an information unit.

In the case where dedicated PCB is used, the electrical connection mayuse an edge connector, relating to the portion of a printed circuitboard (PCB) consisting of traces leading to the edge of the board thatare intended to plug into a matching socket. Such connectors are used incomputers for expansion slots for peripheral cards, such as PCI, PCIExpress, and AGP cards. Edge connector sockets consist of a plastic“box” open on one side, with pins on one or both side(s) of the longeredges, sprung to push into the middle of the open center. Connectors areoften keyed to ensure the correct polarity, and may contain bumps ornotches both for polarity, and to ensure that the wrong type of deviceis not inserted. The socket width is chosen to fit to the thickness ofthe connecting PCB.

Any part of, or the whole of, any of the methods described herein may beprovided as part of, or used as, an Application Programming Interface(API), defined as an intermediary software serving as the interfaceallowing the interaction and data sharing between an applicationsoftware and the application platform, across which few or all servicesare provided, and commonly used to expose or use a specific softwarefunctionality, while protecting the rest of the application. The API maybe based on, or according to, Portable Operating System Interface(POSIX) standard, defining the API along with command line shells andutility interfaces for software compatibility with variants of Unix andother operating systems, such as POSIX.1-2008 that is simultaneouslyIEEE STD. 1003.1™—2008 entitled: “Standard for InformationTechnology—Portable Operating System Interface (POSIX®) Description”,and The Open Group Technical Standard Base Specifications, Issue 7, IEEESTD. 1003.1™, 2013 Edition.

Any part of, or whole of, any of the methods described herein may beimplemented by a processor such as processor 64, and may further be usedin conjunction with various devices and systems, for example a devicemay be a Personal Computer (PC), a desktop computer, a mobile computer,a laptop computer, a notebook computer, a tablet computer, a servercomputer, a handheld computer, a handheld device, a Personal DigitalAssistant (PDA) device, a cellular handset, a handheld PDA device, anon-board device, an off-board device, a hybrid device, a vehiculardevice, a non-vehicular device, a mobile or portable device, or anon-mobile or non-portable device.

The term “port” refers to a place of access to a device, electricalcircuit or network, where energy or signal may be supplied or withdrawn.The term “interface” of a networked device refers to a physicalinterface, a logical interface (e.g., a portion of a physical interfaceor sometimes referred to in the industry as a sub-interface—for example,such as, but not limited to a particular VLAN associated with a networkinterface), and/or a virtual interface (e.g., traffic grouped togetherbased on some characteristic—for example, such as, but not limited to, atunnel interface). As used herein, the term “independent” relating totwo (or more) elements, processes, or functionalities, refers to ascenario where one does not affect nor preclude the other. For example,independent communication such as over a pair of independent data routesmeans that communication over one data route does not affect norpreclude the communication over the other data routes.

Any device herein may be integrated with a part of or in an entireappliance. The primary function of the appliance may be associated withfood storage, handling, or preparation, such as microwave oven, anelectric mixer, a stove, an oven, or an induction cooker for heatingfood, or the appliance may be a refrigerator, a freezer, a foodprocessor, a dishwasher, a food blender, a beverage maker, acoffee-maker, or an iced-tea maker. Alternatively or in addition, theprimary function of the appliance may be associated with anenvironmental control such as temperature control, and the appliance mayconsist of, or may be part of, an HVAC system, an air conditioner or aheater. Alternatively or in addition, the primary function of theappliance may be associated with a cleaning action, such as a washingmachine, a clothes dryer for cleaning clothes, or a vacuum cleaner.Alternatively or in addition, the primary function of the appliance maybe associated with water control or water heating. The appliance may bean answering machine, a telephone set, a home cinema system, a HiFisystem, a CD or DVD player, an electric furnace, a trash compactor, asmoke detector, a light fixture, or a dehumidifier. The appliance may bea handheld computing device or a battery-operated portable electronicdevice, such as a notebook or laptop computer, a media player, acellular phone, a Personal Digital Assistant (PDA), an image processingdevice, a digital camera, or a video recorder. The integration with theappliance may involve sharing a component such as housing in the sameenclosure, sharing the same connector such as sharing a power connectorfor connecting to a power source, where the integration involves sharingthe same connector for being powered from the same power source. Theintegration with the appliance may involve sharing the same powersupply, sharing the same processor, or mounting onto the same surface.

The steps described herein may be sequential, and performed in thedescribed order. For example, in a case where a step is performed inresponse to another step, or upon completion of another step, the stepsare executed one after the other. However, in the case where two or moresteps are not explicitly described as being sequentially executed, thesesteps may be executed in any order or may be simultaneously performed.Two or more steps may be executed by two different network elements, orin the same network element, and may be executed in parallel usingmultiprocessing or multitasking.

A tangible machine-readable medium (such as a storage) may have a set ofinstructions detailing part (or all) of the methods and steps describedherein stored thereon, so that when executed by one or more processors,may cause the one or more processors to perform part of, or all of, themethods and steps described herein. Any of the network elements may be acomputing device that comprises a processor and a computer-readablememory (or any other tangible machine-readable medium), and thecomputer-readable memory may comprise computer-readable instructionssuch that, when read by the processor, the instructions cause theprocessor to perform the one or more of the methods or steps describedherein. Any of the disclosed flow charts or methods, or any stepthereof, may be implemented in the form of software stored on a memoryor a computer-readable non-transitory information storage medium such asan optical or magnetic disk, a non-volatile memory (e.g., Flash or ROM),RAM, and other forms of volatile memory. The information storage mediummay be an internal part of the computer, a removable external elementcoupled to the computer, or unit that is remotely accessible via a wiredor wireless network.

Discussions herein utilizing terms such as, for example, “processing,”“computing,” “calculating,” “determining,” “establishing”, “analyzing”,“checking”, or the like, may refer to operation(s) and/or process(es) ofa computer, a computing platform, a computing system, or otherelectronic computing device, that manipulate and/or transform datarepresented as physical (e.g., electronic) quantities within thecomputer's registers and/or memories into other data similarlyrepresented as physical quantities within the computer's registersand/or memories or other information storage medium that may storeinstructions to perform operations and/or processes.

Throughout the description and claims of this specification, the word“couple”, and variations of that word such as “coupling”, “coupled”, and“couplable”, refer to an electrical connection (such as a copper wire orsoldered connection), a logical connection (such as through logicaldevices of a semiconductor device), a virtual connection (such asthrough randomly assigned memory locations of a memory device) or anyother suitable direct or indirect connections (including combination orseries of connections), for example for allowing the transfer of power,signal, or data, as well as connections formed through interveningdevices or elements.

The arrangements and methods described herein may be implemented usinghardware, software or a combination of both. The term “integration” or“software integration” or any other reference to the integration of twoprograms or processes herein refers to software components (e.g.,programs, modules, functions, processes etc.) that are (directly or viaanother component) combined, working or functioning together or form awhole, commonly for sharing a common purpose or set of objectives. Suchsoftware integration can take the form of sharing the same program code,exchanging data, being managed by the same manager program, executed bythe same processor, stored on the same medium, sharing the same GUI orother user interface, sharing peripheral hardware (such as a monitor,printer, keyboard and memory), sharing data or a database, or being partof a single package. The term “integration” or “hardware integration” orintegration of hardware components herein refers to hardware componentsthat are (directly or via another component) combined, working orfunctioning together or form a whole, commonly for sharing a commonpurpose or set of objectives. Such hardware integration can take theform of sharing the same power source (or power supply) or sharing otherresources, exchanging data or control (e.g., by communicating), beingmanaged by the same manager, physically connected or attached, sharingperipheral hardware connection (such as a monitor, printer, keyboard andmemory), being part of a single package or mounted in a single enclosure(or any other physical collocating), sharing a communication port, orused or controlled by the same software or hardware. The term“integration” herein refers (as applicable) to a software integration,hardware integration, or any combination thereof.

Any network herein may be frame or packet based. Any networking protocolmay be utilized for exchanging information between the network elements(e.g., clients, and servers) within the network (such as the Internet).For example, it is contemplated that communications can be performedusing TCP/IP. Generally, HTTP and HTTPS are utilized on top of TCP/IP asthe message transport envelope. These two protocols can deal withfirewall technology better than other message management techniques.However, partners may choose to use a message-queuing system instead ofHTTP and HTTPS if greater communications reliability is needed. Anon-limiting example of a message queuing system is IBM's MQ-Series orthe Microsoft Message Queue (MSMQ). The system described herein issuited for both HTTP/HTTPS, message-queuing systems, and othercommunications transport protocol technologies. Furthermore, dependingon the differing business and technical requirements of the variouspartners within the network, the physical network may embrace andutilize multiple communication protocol technologies.

A tangible machine-readable medium (such as a storage) may have a set ofinstructions detailing part (or all) of the methods and steps describedherein stored thereon, so that when executed by one or more processors,may cause the one or more processors to perform part of, or all of, themethods and steps described herein. Any of the network elements may be acomputing device that comprises a processor and a computer-readablememory (or any other tangible machine-readable medium), and thecomputer-readable memory may comprise computer-readable instructionssuch that, when read by the processor, the instructions causes theprocessor to perform the one or more of the methods or steps describedherein.

Any device or network element herein may comprise, consists of, orinclude a Personal Computer (PC), a desktop computer, a mobile computer,a laptop computer, a notebook computer, a tablet computer, a servercomputer, a handheld computer, a handheld device, a Personal DigitalAssistant (PDA) device, a cellular handset, a handheld PDA device, anon-board device, an off-board device, a hybrid device, a vehiculardevice, a non-vehicular device, a mobile or portable device, anon-mobile or a non-portable device. Further, any device or networkelement herein may comprise, consist of, or include a major appliance(white goods) and may be an air conditioner, dishwasher, clothes dryer,drying cabinet, freezer, refrigerator, kitchen stove, water heater,washing machine, trash compactor, microwave oven and induction cooker.The appliance may similarly be a ‘small’ appliance such as TV set, CD orDVD player, camcorder, still camera, clock, alarm clock, video gameconsole, HiFi or home cinema, telephone or answering machine.

The term “port” refers to a place of access to a device, electricalcircuit or network, where energy or signal may be supplied or withdrawn.The term “interface” of a networked device refers to a physicalinterface, a logical interface (e.g., a portion of a physical interfaceor sometimes referred to in the industry as a sub-interface—for example,such as, but not limited to a particular VLAN associated with a networkinterface), and/or a virtual interface (e.g., traffic grouped togetherbased on some characteristic—for example, but not limited to, a tunnelinterface). As used herein, the term “independent” relating to two (ormore) elements, processes, or functionalities, refers to a scenariowhere one does not affect nor preclude the other. For example,independent communication such as over a pair of independent data routesmeans that communication over one data route does not affect norpreclude the communication over the other data routes.

As used herein, the term “Integrated Circuit” (IC) shall include anytype of integrated device of any function where the electronic circuitis manufactured by the patterned diffusion of trace elements into thesurface of a thin substrate of semiconductor material (e.g., Silicon),whether single or multiple die, or small or large scale of integration,and irrespective of process or base materials (including, withoutlimitation Si, SiGe, CMOS and GAs) including without limitationapplications specific integrated circuits (ASICs), field programmablegate arrays (FPGAs), digital processors (e.g., DSPs, CISCmicroprocessors, or RISC processors), so-called “system-on-a-chip” (SoC)devices, memory (e.g., DRAM, SRAM, flash memory, ROM), mixed-signaldevices, and analog ICs. The circuits in an IC are typically containedin a silicon piece or in a semiconductor wafer, and commonly packaged asa unit. The solid-state circuits commonly include interconnected activeand passive devices, diffused into a single silicon chip. Integratedcircuits can be classified into analog, digital and mixed signal (bothanalog and digital on the same chip). Digital integrated circuitscommonly contain many of logic gates, flip-flops, multiplexers, andother circuits in a few square millimeters. The small size of thesecircuits allows high speed, low power dissipation, and reducedmanufacturing cost compared with board-level integration. Further, aMulti-Chip Module (MCM) may be used, where multiple Integrated Circuits(ICs), the semiconductor dies, or other discrete components are packagedonto a unifying substrate, facilitating their use as a single component(as though a larger IC).

The term “computer” is used generically herein to describe any number ofcomputers, including, but not limited to personal computers, embeddedprocessing elements and systems, control logic, ASICs, chips,workstations, mainframes, etc. Any computer herein may consist of, or bepart of, a handheld computer, including any portable computer, which issmall enough to be held and operated while holding in one hand, or fitinto a pocket. Such a device, also referred to as a mobile device,typically has a display screen with a touch input and/or a miniaturekeyboard. Non-limiting examples of such devices include Digital StillCamera (DSC), Digital video Camera (DVC or digital camcorder), PersonalDigital Assistant (PDA), and mobile phones and Smartphones.

The mobile devices may combine video, audio and advanced communicationscapabilities, such as PAN and WLAN. A mobile phone (also known as acellular phone, cell phone and a hand phone) is a device which can makeand receive telephone calls over a radio link whilst moving around awide geographic area, by connecting to a cellular network provided by amobile network operator. The calls are to and from the public telephonenetwork, which includes other mobiles and fixed-line phones across theworld. The Smartphones may combine the functions of a personal digitalassistant (PDA), and may serve as portable media players and cameraphones with high-resolution touch-screens, web browsers that can access,and properly display, standard web pages rather than justmobile-optimized sites, GPS navigation, Wi-Fi and mobile broadbandaccess. In addition to telephony, the Smartphones may support a widevariety of other services such as text messaging, MMS, email, Internetaccess, short-range wireless communications (infrared, Bluetooth),business applications, gaming and photography.

As used herein, the terms “program”, “programmable”, and “computerprogram” are meant to include any sequence or human or machinecognizable steps that perform a function. Such programs are notinherently related to any particular computer or other apparatus, andmay be rendered in virtually any programming language or environmentincluding, for example, C/C++, Fortran, COBOL, PASCAL, assemblylanguage, markup languages (e.g., HTML, SGML, XML, VoXML), and thelikes, as well as object-oriented environments such as the Common ObjectRequest Broker Architecture (CORBA), Java™ (including J2ME, Java Beans,etc.) and the like, as well as in firmware or other implementations.Generally, program modules include routines, programs, objects,components, data structures, etc., that performs particular tasks orimplement particular abstract data types.

The terms “task” and “process” are used generically herein to describeany type of running programs, including, but not limited to a computerprocess, task, thread, executing application, operating system, userprocess, device driver, native code, machine or other language, etc.,and can be interactive and/or non-interactive, executing locally and/orremotely, executing in foreground and/or background, executing in theuser and/or operating system address spaces, a routine of a libraryand/or standalone application, and is not limited to any particularmemory partitioning technique. The steps, connections, and processing ofsignals and information illustrated in the figures, including, but notlimited to any block and flow diagrams and message sequence charts, maytypically be performed in the same or in a different serial or parallelordering and/or by different components and/or processes, threads, etc.,and/or over different connections and be combined with other functionsin other embodiments, unless this disables the embodiment or a sequenceis explicitly or implicitly required (e.g., for a sequence of readingthe value, processing the value—the value must be obtained prior toprocessing it, although some of the associated processing may beperformed prior to, concurrently with, and/or after the read operation).Where certain process steps are described in a particular order or wherealphabetic and/or alphanumeric labels are used to identify certainsteps, the embodiments of the invention are not limited to anyparticular order of carrying out such steps. In particular, the labelsare used merely for convenient identification of steps, and are notintended to imply, specify or require a particular order for carryingout such steps. Furthermore, other embodiments may use more or lesssteps than those discussed herein. The invention may also be practicedin distributed computing environments where tasks are performed byremote processing devices that are linked through a communicationsnetwork. In a distributed computing environment, program modules may belocated in both local and remote memory storage devices.

Any wired network herein may be based on a LAN communication, such asEthernet, and may be partly or in full in accordance with the IEEE802.3standard. For example, Gigabit Ethernet (GbE or 1 GigE) may be used,describing various technologies for transmitting Ethernet frames at arate of a gigabit per second (1,000,000,000 bits per second), as definedby the IEEE 802.3-2008 standard. There are five physical layer standardsfor gigabit Ethernet using optical fiber (1000BASE-X), twisted paircable (1000BASE-T), or balanced copper cable (1000BASE-CX). The IEEE802.3z standard includes 1000BASE-SX for transmission over multi-modefiber, 1000BASE-LX for transmission over single-mode fiber, and thenearly obsolete 1000BASE-CX for transmission over balanced coppercabling. These standards use 8b/10b encoding, which inflates the linerate by 25%, from 1000 Mbit/s to 1250 Mbit/s, to ensure a DC balancedsignal. The symbols are then sent using NRZ. The IEEE 802.3ab, whichdefines the widely used 1000BASE-T interface type, uses a differentencoding scheme in order to keep the symbol rate as low as possible,allowing transmission over twisted pair. Similarly, The 10 gigabitEthernet (10GE or 10 GbE or 10 GigE may be used, which is a version ofEthernet with a nominal data rate of 10 Gbit/s (billion bits persecond), ten times faster than gigabit Ethernet. The 10 Gigabit Ethernetstandard only defines full duplex point-to-point links that aregenerally connected by network switches. The 10 Gigabit Ethernetstandard encompasses a number of different physical layers (PHY)standards. A networking device may support different PHY types throughpluggable PHY modules, such as those based on SFP+.

As used herein, the terms “network”, “communication link” and“communications mechanism” are used generically to describe one or morenetworks, communications media or communications systems, including, butnot limited to, the Internet, private or public telephone, cellular,wireless, satellite, cable, data networks. Data networks include, butnot limited to, Metropolitan Area Networks (MANs), Wide Area Networks(WANs), Local Area Networks (LANs), Personal Area networks (PANs), WLANs(Wireless LANs), Internet, internets, NGN, intranets, Hybrid Fiber Coax(HFC) networks, satellite networks, and Telco networks. Communicationmedia include, but not limited to, a cable, an electrical connection, abus, and internal communications mechanisms such as message passing,interprocess communications, and shared memory. Such networks orportions thereof may utilize any one or more different topologies (e.g.,ring, bus, star, loop, etc.), transmission media (e.g., wired/RF cable,RF wireless, millimeter wave, optical, etc.) and/or communications ornetworking protocols (e.g., SONET, DOCSIS, IEEE Std. 802.3, ATM, X.25,Frame Relay, 3GPP, 3GPP2, WAP, SIP, UDP, FTP, RTP/RTCP, H.323, etc.).While exampled herein with regard to secured communication between apair of network endpoint devices (host-to-host), the described methodcan equally be used to protect the data flow between a pair of gatewaysor any other networking-associated devices (network-to-network), orbetween a network device (e.g., security gateway) and a host(network-to-host).

The corresponding structures, materials, acts, and equivalents of allmeans plus function elements in the claims below are intended to includeany structure, or material, for performing the function in combinationwith other claimed elements as specifically claimed. The description ofthe present invention has been presented for purposes of illustrationand description, but is not intended to be exhaustive, or limited to theinvention in the form disclosed. The present invention should not beconsidered limited to the particular embodiments described above, butrather should be understood to cover all aspects of the invention asfairly set out in the attached claims. Various modifications, equivalentprocesses, as well as numerous structures to which the present inventionmay be applicable, will be readily apparent to those skilled in the artto which the present invention is directed upon review of the presentdisclosure.

All publications, standards, patents, and patent applications cited inthis specification are incorporated herein by reference as if eachindividual publication, patent, or patent application were specificallyand individually indicated to be incorporated by reference and set forthin its entirety herein.

The invention claimed is:
 1. A device for a lossless and statelessde-compression scheme, for use with a group of multiple frames that areaccording to a first protocol and include, in a fixed location in theframes, a first fixed length payload consisting of M bits, wherein thenumber of values in the first payload is equal to, or less than, 2^(N)possible values, the device comprising: a connector for connecting to avehicle bus; a receiver coupled to the connector for receiving from thevehicle bus a plurality of frames according to a second protocol thatdefines a fixed length payload consisting of N bits that are derivedfrom the first protocol using a set of rules; a software and a processorfor executing the software; a memory coupled to the processor forstoring the set of rules; a port coupled to the processor for outputtinga signal in response to a second frame that is according to the firstprotocol; and a single enclosure housing the connector, the receiver,the processor, the memory, and the port, wherein the processor isoperative in real-time to, for each of a received first frame out of theplurality of frames, to identify and extract a first N-bit payload fromthe received first frame, to map according to the stored set of rulesthe first payload to a second payload consisting of M bits (M>N), byrespectively associating a single M-bit value to the extracted firstpayload N-bit value, and to construct the second frame that includes thesecond M-bit payload and is part of the group, wherein the set of rulesis based on calculated stateless correlation information between two ormore bit-locations in multiple M-bit sets that represent all possiblecombinations of the first payload of the first protocol.
 2. The deviceaccording to claim 1, for use with a number Q where Q>1 and Q<M, whereinthe mapping comprises calculating a value of at least one of the M bitsor locations of the second payload based on the values of Q−1 locationsor bits in the N bits or locations of the first payload.
 3. The deviceaccording to claim 2, wherein Q=2, 3, 4, 5, 6, 8, 10, 12, 15, or
 20. 4.The device according to claim 2, further repeated for all Q from 2 toM−1.
 5. The device according to claim 2, wherein the calculating isbased on, or using, Boolean operation of the Q−1 locations or bits. 6.The device according to claim 2, further repeating the calculating,wherein the calculated value of the at least one of the M bits orlocations is used for calculating another at least one of the M bits orlocations.
 7. The device according to claim 2, for use with a functionthat maps values of Q−1 bits to Q bits, wherein the calculatingcomprises mapping the value of the Q−1 locations or bits to a value of Qbits, and wherein the Q bits are assigned to Q locations or bits in theM bits or locations of the second payload.
 8. The device according toclaim 2, wherein at least one of the received first frames comprises afirst field that comprises the location of each of the at least one ofthe M bits or locations of the second payload and a respective secondfield that comprises a value for each of the at least one of the M bitsor locations, and wherein the mapping comprises calculating a value ofat least one of the M bits or locations of the second payload based onthe value of the respective second field.
 9. The device according toclaim 8, wherein the first or second field is carried in a field definedby the second protocol.
 10. The device according to claim 9, wherein thesecond protocol consists of, employs, uses, is based on, or iscompatible with, a Controller Area Network (CAN), and wherein the firstor second field consists of, employs, uses, is based on, or iscompatible with, a Data Length Code (DLC) field.
 11. The deviceaccording to claim 1, wherein part of, or all of, the received pluralityof frames further include a code in a fixed length code field distinctfrom the fixed length payload consisting of N bits, and wherein thedevice further operative for, for each of the received first frame thatincludes the code, identifying and extracting the code from the receivedfirst frame.
 12. The device according to claim 11, wherein all of thereceived plurality of frames further include the code in a code field.13. The device according to claim 11, wherein the second protocoldefines a fixed length payload consisting of Q bits, and wherein thecode field length is equal to, or less than, Q−N.
 14. The deviceaccording to claim 13, wherein the code field length is equal to Q−N.15. The device according to claim 13, wherein N=M.
 16. The deviceaccording to claim 11, wherein the code relates to, or is associatedwith, the first or second payload, and wherein the sending comprisesusing, or basing on, the extracted code from the code field.
 17. Thedevice according to claim 11, for use with an authentication scheme,wherein the code supports, is part of, or is associated with, theauthentication scheme.
 18. The device according to claim 1, wherein themapping comprises calculating a Boolean logic using logic gates for eachone of the M bits or locations of the second payload that is based onone or more of the N bits or locations of the first payload.
 19. Thedevice according to claim 1, wherein at least one of the M bits orlocations of the second payload is assigned as ‘0’ or ‘1’ for anyreceived first payload.
 20. The device according to claim 1, wherein atleast one of the M bits or locations of the second payload is calculatedusing two of the N bits or locations of the first payload.
 21. Thedevice according to claim 1, wherein at least one of the M bits orlocations of the second payload is calculated using three or more of theN bits or locations of the first payload.
 22. The device according toclaim 1, wherein at least one of the M bits or locations of the secondpayload is calculated using all of the N bits or locations of the firstpayload.
 23. The device according to claim 22, wherein each of the Mbits or locations of the second payload is calculated using all of the Nbits or locations of the first payload.
 24. The device according toclaim 22, wherein the memory stores a set of coefficients (c₀, c₁, c₂,c₃, . . . c_(N-3), c_(N-2), c_(N-1), c_(N)), and wherein at least one ofthe N bits or locations of the first payload is calculated using the setof coefficients and the N bits or locations of the first payload definedas (b₀, b₁, b₂, b₃, . . . b_(N-3), b_(N-2), b_(N-1)).
 25. The deviceaccording to claim 24, wherein the memory stores M sets of coefficients,and wherein each of the N bits or locations of the first payload iscalculated using a respective set of coefficients and the N bits orlocations of the first payload.
 26. The device according to claim 1,wherein the device is part of, attachable to, or comprised in, avehicle.
 27. The device according to claim 1, further consists of,integrated with, or is part of, an Electronic Control Unit (ECU) in avehicle.
 28. The device according to claim 27, wherein the ElectronicControl Unit (ECU) is selected from the group consisting ofElectronic/engine Control Module (ECM), Engine Control Unit (ECU),Powertrain Control Module (PCM), Transmission Control Module (TCM),Brake Control Module (BCM or EBCM), Central Control Module (CCM),Central Timing Module (CTM), General Electronic Module (GEM), BodyControl Module (BCM), Suspension Control Module (SCM), (PSCU), SeatControl Unit, Speed Control Unit (SCU), Telematic Control Unit (TCU),Transmission Control Unit (TCU), Brake Control Module (BCM; ABS, orESC), Battery management system, control unit, and a control module. 29.The device according to claim 27, wherein the Electronic Control Unit(ECU) contains or executes software, an operating-system, or amiddleware, that comprises, or uses OSEK/VDX, International Organizationfor Standardization (ISO) 17356-1, ISO 17356-2, ISO 17356-3, ISO17356-4, ISO 17356-5, or AUTOSAR standard.
 30. The device according toclaim 1, wherein at least one of the received first frames comprises QN-bit first payloads.
 31. The device according to claim 30, wherein eachof most of, or all of, the received first frames comprise multiple N-bitfirst payloads.
 32. The device according to claim 30, wherein theidentifying and extracting by the processor comprises identifying andextracting of the Q first N-bit payloads from the received first frame,and wherein the mapping of the first payload to a second payloadconsisting of M bits.
 33. The device according to claim 1, wherein thefirst protocol is identical to the second protocol.
 34. The deviceaccording to claim 1, wherein the first protocol is different from thesecond protocol.
 35. The device according to claim 1, wherein each ofthe first and second protocols includes, or is based on, or is accordingto, an Open Systems Interconnection (OSI) Layer-2 protocol.
 36. Thedevice according to claim 1, wherein the ratio M/N is equal to, or ismore than, 1.1, 1.2, 1.5, 2, 2.5, 3, 3.5, 5, 7, 10, 15, 20, 30, 50, or100.
 37. The device according to claim 1, wherein the ratio M/N is lessthan 1.2, 1.5, 2, 2.5, 3, 3.5, 5, 7, 10, 15, 20, 30, 50, or
 100. 38. Thedevice according to claim 1, wherein the ratio 2^(M)/2^(N)=2^(M-N) isequal to, or is more than, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, or2048.
 39. The device according to claim 1, wherein the ratio2^(M)/2^(N)=2^(M-N) is less than 4, 8, 16, 32, 64, 128, 256, 512, 1024,or
 2048. 40. The device according to claim 1, wherein the memorycomprises N address lines or bits input and M data lines or bits output,and wherein the mapping comprises applying or writing the N-bit payloadvalue as address and reading the M-bit value as output data.
 41. Thedevice according to claim 1, further operative for: receiving orobtaining an additional frame according to the second protocol thatincludes a payload consisting of M bits; constructing an additionalsecond frame according to the first protocol that includes the receivedM-bit unchanged payload; and sending the constructed additional secondframe.
 42. The device according to claim 1, wherein each of the receivedplurality of frames includes an indicator bit value, the device isfurther operative for: receiving or obtaining an additional frameaccording to the second protocol that includes a payload consisting of Mbits, responsive to the indicator bit value, constructing an additionalsecond frame according to the first protocol that includes the receivedM-bit unchanged payload; and using or sending the constructed additionalsecond frame.
 43. The device according to claim 42, wherein theindicator bit value is carried in a field defined by the secondprotocol.
 44. The device according to claim 43, wherein the secondprotocol consists of, employs, uses, is based on, or is compatible with,a Controller Area Network (CAN), and wherein the field consists of,employs, uses, is based on, or is compatible with, a Data Length Code(DLC) field.
 45. The device according to claim 1, wherein the firstprotocol or the second protocol uses, is according to, or comprises, avehicle bus protocol.
 46. The device according to claim 45, wherein adata link layer or a physical layer signaling of the vehicle busprotocol is according to, based on, uses, or is compatible with, ISO11898-1:2015 or standard.
 47. The device according to claim 45, whereinthe vehicle bus uses, or is compatible with, a multi-master, serialprotocol using acknowledgement, arbitration, and error-detectionschemes.
 48. The device according to claim 47, wherein the vehicle busconsists of, employs, uses, is based on, or is compatible with, aController Area Network (CAN).
 49. The device according to claim 48,wherein the CAN is according to, based on, uses, or is compatible with,a standard selected from the group consisting of ISO 11898-3:2006, ISO11898-2:2004, ISO 11898-5:2007, ISO 11898-6:2013, ISO 11992-1:2003, ISO11783-2:2012, SAE J1939/11_201209, SAE J1939/15_201508, On-BoardDiagnostics (OBD), and SAE J2411_200002.
 50. The device according toclaim 48, wherein the CAN is according to, based on, uses, or iscompatible with, Flexible Data-Rate (CAN FD) protocol.